2014 apics production and inventory management journal
TRANSCRIPT
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PRODUCTION AND INVENTORY
MANAGEMENT JOURNAL
VOLUME 49, NO. 1 2014
A Concepual Framework for Invenory Managemen:
Focusing on Low-Consumpion Iems
Peter Wanke
Inegraing FMEA wih he Supply Chain Risk Managemen
Processes o Faciliae Supply Chain Design Decisions
V.M. Rao Tummala, Tobias Schoenherr, CSCP, Thomas Harrison
Operaions Managemen Salary Repor
L. Drew Rosen, Thomas Janicki, Judith Gebauer
A Tuorial on Managerial Cos Accouning: Year-End Reporing
Timothy D. Fry, Kirk D. Fiedler
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL2
ABOUT THE PRODUCTION AND INVENTORY
MANAGEMENT JOURNAL
Through he suppor of APICS Foundaion, he P&IM Journal is commited
o being he premier oule for managerial-focused research in operaionsand supply chain managemen. The APICS Foundaion 2014 board officersand members are:
President:Karl Klaesius, CPIM, KS&E Enerprises
Vice President: Shari Ruelas, CPIM, CSCP, Chevron Producs
Treasurer: Rober Vokurka, PhD, CPIM, CIRM, CSCP
Barbara Flynn, PhD, Richard M. and Myra Louise Buskirk Professor ofManufacuring Managemen, Kelley School of Business, Indiana Universiy
Alan Dunn, CPIM, GDI Consuling and Training Company
Kaie Fowler, Schlumberger
Anonio Galvao, CSCP, Sealed Air Inc.
Michael Wasson, CSCP, Coca-Cola Norh America
Paul Pitman, PhD, Indiana Universiy Souheas
Marco Ugare, PhD, CPIM, CSCP, MillerCoors
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TABLE OF CONTENTS
PRODUCTION AND INVENTORY
MANAGEMENT JOURNAL
Articles
A Conceptual Framework for Inventory Management: Focusing on
Low-Consumption Items
by Peer Wanke
Integrating FMEA with the Supply Chain Risk Management Processes
to Facilitate Supply Chain Design Decisionsby V.M. Rao Tummala, Tobias Schoenherr, CSCP and Thomas Harrison
Operations Management Salary Report
by L. Drew Rosen, Thomas Janicki, Judih Gebauer
A Tutorial on Managerial Cost Accounting: Year-End Reporting
by Timohy D. Fry, Kirk D. Fiedler
Editorial Staff Information
Robert L. BregmanEdior in Chief
Associae Professor
Decision and Informaion Sciences Deparmen
Universiy of Houson
6
24
71
83
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL4
ARTICLE SUMMARIES
A CONCEPTUAL FRAMEWORK FOR INVENTORY MANAGEMENT:
FOCUSING ON LOW CONSUMPTION
This aricle evaluaes he premise o demand adherence o normal disribuion
in invenory managemen models, showing ha his can lead o significan
disorions, mainly o sock conrol o very low and low consumpion iems.
The aricle hus proposes a ramework o help managers deermine he bes
sock policy o be adoped given produc demand characerisics. The aricle
also presens he use o such a ramework in a case sudy, in an atemp o
illusrae he benefis o adoping probabiliy densiy uncions ha are more
adequae o produc demand characerisics, in erms o oal coss o socks.
INTEGRATING FMEA WITH THE SUPPLY CHAIN RISK
MANAGEMENT PROCESS TO FACILITATE SUPPLY CHAIN
DESIGN DECISIONS
We presen a novel approach o inegraing ailure mode and effec analysis
(FMEA) wih a supply chain risk managemen process (SCRMP). Focusing on
he challenging ask o assess and manage supply-side risks in global supply
chains, he approach developed offers an effecive and affordable way or
firms o provide decision suppor or he selecion o heir mos appropriae
supply chain design. The aim o he inegraed approach combining he
srenghs o FMEA and SCRMP is o gaher as much perinen inormaion
as possible, o srucure i, and o comprehensively delineae all poenialsupply chain risk acors, offering valuable decision suppor. We illusrae
he applicaion o he approach a Michigan Ladder Company, where i was
applied o wo specific supply chains or he procuremen o fiberglass ladders.
Specifically, one supply chain spanned rom China o he U.S. via Mexico
(aking advanage o a Mexican maquiladora), and one spanned rom China
direcly o he U.S. The combinaion o FMEA and he SCRMP enhanced he
manuacurers confidence in is supply chain design decision, and enabled he
firm o proacively manage is supply-side risks. Overall, he aricle is mean o
moivae praciioners o embark on he journey o acive risk managemen.
While some may perceive risk managemen as a dauning ask or being
primarily employed by larger firms, we provide guidance or firms o any sizeo apply he approach i can be done, and does no have o consume an
inordinae amoun o resources.
OPERATIONS MANAGEMENT SALARY REPORT
APICS, in conjuncion wih he Cameron School o Business a he Universiy
o Norh Carolina Wilmingon, is pleased o provide he resuls o he 2013
Operaions Managemen Salary Repor. The daa are colleced rom a random
sample o more han 30,000 operaions managemen proessionals worldwide.
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VOLUME 49, NO. 1 5
Twice annually, approximaely fify percen o he APICS membership and
cusomer base receives a reques o complee an online survey collecing daa
concerning curren salary and compensaion by job uncion and ile. The
survey can be accessed a: htp://csbapp.uncw.edu/apics/.
A TUTORIAL ON MANAGERIAL COST ACCOUNTING: YEAREND
REPORTING
Building on he companion aricle A Tuorial on Managerial Cos Accouning:
Living wih Variances by Fry and Fiedler (2011), his curren paper picks
up where he previous paper lef off and illusraes how he managemen
accouning sysem (MCA) is linked o financial accouning (FA) o generae
he year-end financial repors required by shareholders, banks, and he IRS.
The prior paper ocused on he deailed use o inormaion provided by he
MCA hroughou he year and walked hrough he developmen o he yearly
budge, calculaion o produc coss, deerminaion o budge variances,
derivaion o he periodic income and saemen o cash flows repors, and
provides possible examples o dysuncional behavior a a ficiious company
called Mandrake Manuacuring. This uorial concenraes on he ineracion
o he MCA and FA sysems and he producion o year end FA saemens. In
addiion o providing inormaion such as cos o goods sold, invenory values,
and operaing sandards o he FA, he year-end inormaion provided by he
MCA is also used o develop nex years budges. In his presen paper, he
conversion o he MCA repors ino he FA repors will be presened. Also, he
impac o he MCA repors on uure budges will be discussed. As poinedou in F&F, i is vial ha operaions managers undersand how he accouning
sysems used by heir company uncion. Wihou such undersanding, many
o he problems associaed wih he improper use o he accouning sysems
will never be correced.
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL6
A CONCEPTUAL FRAMEWORK FOR
INVENTORY MANAGEMENT: FOCUSING ON
LOW CONSUMPTION ITEMS
Peer Wanke (Corresponding Auhor)
Center for Logistics Studies, Infrastructure, and Management, The COPPEAD
Graduate School of Business, Federal University of Rio de Janeiro, Rio de
Janeiro Brazil 21949-900
ABSTRACT
This aricle evaluaes he premise o demand adherence o normal disribuion
in invenory managemen models, showing ha his can lead o significandisorions, mainly o sock conrol o very low and low consumpion iems.
The aricle hus proposes a ramework o help managers deermine he bes
sock policy o be adoped given produc demand characerisics. The aricle
also presens he use o such a ramework in a case sudy, in an atemp o
illusrae he benefis o adoping probabiliy densiy uncions ha are more
adequae o produc demand characerisics, in erms o oal coss o socks.
Keywords: sock, lead-ime demand, coefficien o variaion, ramework, coss
. Introduction
Invenory managemen permeaes decision-making in counless firmsand has been exensively sudied in he academic and corporae spheres
(Rosa e al. 2010). The key quesions usually influenced by a variey o
circumsances which invenory managemen seeks o answer are: when
o order, how much o order and how much sock o keep as saey sock
(Nami and Chen 1999; Silva 2009). According o Wanke (2011a), invenory
managemen involves a se o decisions ha aim a maching exising
demand wih he supply o producs and maerials over space and ime
in order o achieve specified cos and service level objecives, observing
produc, operaion, and demand characerisics.
These diverse circumsances ha should be aken ino accoun or anappropriae selecion o invenory managemen models have conribued
o he developmen o research and producion o aricles on possible
qualiaive concepual schemes also known as classificaion approaches
aimed a supporing decision-making (Huiskonen 2001). There are several
examples o his kind hroughou he years.
Williams (1984), or example, developed an analyical mehod o classiy
demand as regular (high consumpion), low consumpion, or inermiten, by
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VOLUME 49, NO. 1 7
decomposing he variabiliy o lead-ime demand ino hree pars: variabiliy
o he number o occurrences per uni o ime, variabiliy o demand size,
and lead-ime variabiliy. Boter and Foruin (2000) based heir classificaion
o iems on hree crieria: lead ime, price, and consumpion level, which
underpin he developmen o eigh differen invenory managemen models.
Eaves and Kingsman (2004) revisied Williams (1984) model, reclassiying
spare pars ino five caegories: smooh, erraic, low urnover, slighly
sporadic, and srongly sporadic. Syneos, Boylan and Croson (2005) classiy
iems ino our quadrans, divided by wo axes: he average demand inerval
and he squared coefficien o demand variaion. Years laer Boylan, Syneos,
and Karakosas (2008) presened an applicaion o his mehod in a sofware
firm. The iems consumpion patern is classified as srongly sporadic,
slighly sporadic, and non-sporadic.
The aim o his aricle is o analyze he patern o demand as he main
inervening acor in invenory managemen. I firs o all discusses, in secion
2, how he requenly adoped premises regarding he adherence o demand
o Normal disribuion may no be realisic and cause disorions, especially
in he case o very low when he annual demand is less han one and low
consumpion iems when he annual demand ranges beween one and
a value sufficienly high, say hree hundred or five hundred unis per year,
in order o characerize a daily demand close o one. Secion 3 proposes a
concepual ramework designed o suppor invenory managemen, which
synhesizes hose models ha are mos adequae or specific paterns odemand (mean and variabiliy). Finally, secions 4 and 5 presen a case sudy
underaken in a Brazilian company, which no only showed he pracical
applicaion o he concepual ramework bu also revealed he laters impac
in erms o shorage and excess coss.
. Literature Review
Choosing he mos adequae invenory managemen model is essenially an
empirically-based decision ha may involve he use o simulaion, scenario
analysis, incremenal cos analyses (Silva 2009; Rosa e al. 2010; Rego and
Mesquia, 2011; Wanke 2011b) or qualiaive concepual schemes also known
as classificaion approaches (Huiskonen 2001). The later usually considersha he impac o produc, operaion and demand characerisics consiue
inervening variables in his choice (see, or example, Williams 1984; Hax and
Candea 1984; Dekker, Klen, and De Roo 1998; Boter and Foruin 2000;
Braglia, Grassi, and Monanari 2004; Eaves and Kingsman 2004; Wanke 2011b).
An analysis o he lieraure dealing wih invenory managemen model
selecion shows ha i originally ocused on producion and disribuion
environmens in which demand and lead ime end o be more predicable
or, in oher words, in which i is easier o answer he quesions o wha and
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL8
how much o order (Wanke and Saliby, 2009; Wanke 2011b; Rosa e al. 2010).
However, here is a growing lieraure relaed o he specific problems raised by
low and very low consumpion iems such as spare pars (Boter and Foruin
2000; Silva, 2009; Rego and Mesquia 2011; Syneos e al. 2012).
The inrinsic characerisics o spare pars, which are ypically low and very
low consumpion iems, make he choice o invenory managemen models
paricularly criical under he ollowing circumsances (Cohen and Lee 1990;
Cohen, Zheng, and Agrawal 1997; Mucksad 2004; Kumar 2005; Rego 2006):
low sock urnover, difficul predicabiliy, longer replenishmen imes, greaer
service level demands and higher acquisiion coss.
Thereore, hese special eaures o spare pars deermine he selecion o
appropriae invenory managemen models. According o Boter and Foruin
(2000), here is a consensus ha spare pars canno be managed using radiional
models (see, or example, hose presened in Rosa e al. 2010). Basically, spare
pars do no fi hese models main premises such as, or example, he adherence
o demand o symmeric and coninuous probabiliy densiy uncions (Silva 2009).
The ollowing subsecions explore his issue a greaer deph, linking demand
characerisics (mean and variabiliy) o invenory managemen models
developed in he lieraure. In he case o average demand, he lieraure
provides he basis or he segmenaion o annual consumpion according
o hree differen levels very low consumpion, low consumpion and massconsumpion (Ward, 1978; Silva, 2009; Wanke, 2011a) while he coefficien o
variaion (see or insance, Silver e al., 1998; Hopp and Spearman, 2008) and
he probabiliy disribuion uncions (see or insance, Yeh, 1997; Silver e al.,
1998) orm he basis or segmenaion in he case o variabiliy.
. Very low consumption
According o Tavares and Almeida (1983), very low consumpion pars are
hose whose average consumpion is less han one uni per year. According o
hese auhors, he sock conrol o hese iems should no be perormed using
he usual models because, due o heir paricular consumpion characerisic,
here are no enough previous occurrences o make a precise esimae oprobabiliy disribuion (Croson 1972; Syneos and Boylan 2001; Ghobbar and
Friend 2003; Eaves and Kingsman 2004; Willemain, Smar, and Schwarz 2004;
Regatieri e al. 2005; Hua e al. 2007; Guierrez, Solis, and Mukhopadhyay
2008; Gomez 2008; Teuner and Duncan 2009).
In addiion, ollowing Tavares and Almeida (1983), i is he analysis o oal shorage,
excess and order placemen coss, given a cerain service level, ha makes i
possible o deermine wheher a par should, or should no, be kep in sock, and a
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VOLUME 49, NO. 1 9
replenishmen reques made solely agains an order. Thus, a binary oal cos model
was developed o suppor decision-making regarding wheher o keep one (1) or
no (0) uni in sock based on wo supposiions: adherence o demand o Poisson
disribuion and he possibiliy o placing an emergency order wih a lower han
usual lead ime, whenever a shorage occurs. This model is presened in appendix 1.
. Low consumption
For he purpose o his aricle, low cos iems are hose wih a hisorical
consumpion o beween 1 and 300~500 unis per year, which leads o an
average daily demand close o one, as suggesed by Wanke (2005). As demand
is no oo small o use he model proposed by Tavares and Almeida (1983),
service level-relaed decisions such as he order poin and replenishmen
level assume greaer imporance. Thus, he model, which is widely used in he
lieraure, was considered o be he mos adequae (Rosa e al. 2010).
More precisely, he model involves a coninuous review o sock levels and
replenishmen orders are always placed whenever he sock posiion reaches
he order poin s (Silver and Peerson 1985; Silver e al. 1998). In his case, a
quaniy o replenishmen is used ha is sufficien o raise he sock posiion
o poin S. Tha is, in pracice, he lo size is . According o Hadley and Whiin
(1961), he models resul in uniary lo size orders when order placemen
coss are low. Thus, as Feeney and Sherbrooke (1966) conclude, he policy
consiues a paricular case o models.
Various auhors (Feeney and Sherbrooke 1966; Walker 1997; Porras and Decker2008; Gomes and Wanke 2008) have used he model in spare par invenory
managemen. Using his model, a replenishmen order is requesed as soon as
a uni o sock is consumed in order o recompose he maximum level o sock.
This model is appropriae or very cosly componens ha are essenial or
business operaions (Walker 1997).
In relaion o he probabiliy disribuions o demand and lead ime in he
conex o models, Rosenshine e al. (1976 and Dhakar e al. 1993) iniially
assume ha lead ime is deerminisic. However, various disribuions, have
been considered in he conex o in order o represen he behavior o demand
or lead ime separaely: Normal (Krupp 1997), Gama (Burgin 1975; Das 1976;Yeh 1997), Poisson (Hill, Omar, and Smih 1999) and empirical disribuion wih
sochasic demands and lead imes (Eppen and Marin 1988).
Anoher imporan poin involves he deerminaion o he probabiliy
disribuion ha resuls rom he combinaion o lead-ime demand resuls
(Lau 1989; Silva 2009). According o Tyworh (1992), heNormal disribuion
consiues a reasonable approximaion or high consumpion iems, bu no or
low consumpion ones. In he case o he later iems, disribuion is ypically
asymmeric and possesses a high probabiliy o demand equal o zero. Porras
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL10
and Decker (2008) adoped he Poisson disribuion o esimae he lead-ime
demand o iems wih only one occurrence a each specific ime inerval.
I should be highlighed ha when demand involves more han one
occurrence per ime inerval, various auhors have proposed compound
models, such as he Sutering Poisson (Ward 1978) , he compound
Poisson model (Williams 1984; Silver, Ho, and Deemer 1971) or he
compound Bernoulli model (Janssen, Heus, and Kok 1998; Srbosch,
Heus, and Schoo 2000). More recenly, Syneos e al. (2012) conduced
a comprehensive lieraure review on he disribuional assumpions
or spare-pars managemen, assessing he goodness-o-fi o various
disribuions and heir sock-conrol implicaions in erms o invenories
held and service levels achieved.
However, since mos o he disribuional assumpions are difficul o
apply in pracice as he parameers o more han one disribuion mus
be deermined firs so as o analyze he lead-ime demand behavior and
in order o make he concepual ramework developed in his research
operaional o managers, readily o be implemened in Excel spreadshees,
we decided o narrow he decision regarding he mos adequae lead-
ime demand disribuion beween Poisson and Gamma disribuions. For
examples on he pracically o he implemenaion o hese disribuions in
Excel, readers should reer, or insance, o Hopp and Spearman (2008) and
Wanke (2011a) or Poisson disribuion and Silver e al. (1998) and Tyworhand Ganeshan (2000) or Gamma disribuion. Besides, as deailed nex,
hese disribuions hold sraighorward relaions beween heir defining
parameers and he mean and variance o he variable o ineres.
... Poisson Distribution
In he case o low consumpion iems, Silver e al. (1998) sugges adoping
he Poisson disribuion premise (c. Appendix 2). According o Yeh (1997 ),
however, i is firs o all necessary o veri y he pracical applicabiliy o he
Poisson disribuion. This is because, in he Poisson disribuion, he mean
and variance are numerically equal. Thus, i his disribuion is o be used
in pracice, he variance o demand mus be siuaed wihin an inervaldelimied by a variaion o en percen around is mean: 0.9ED
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VOLUME 49, NO. 1 1
Gamma disribuion adheres easily o real daa and can be mahemaically
manipulaed in invenory managemen.
Following Yeh e al. (1997), he Gamma disribuion is adequae in cases where
periods wih null demand occur more requenly. Under hese circumsances,
i makes sense o consider he ime inerval ha has elapsed beween wo
consecuive demands differen rom zero as a variable o ineres or modeling
purposes, besides demand isel and lead ime. Segersed (1994 and Yeh
1997), or example, developed an invenory managemen model assuming ha
he ime inerval beween wo consecuive non-zero demands (Ti), demand ()
and lead ime (TR) are adheren o he Gamma disribuion.
I is worh noing ha inermiten demand paterns meaning ha demand
arrives inrequenly and is inerspersed by ime periods wih no demand a all
is a criical or choosing he mos adequae disribuional assumpion (Eaves,
2002; Syneos e al., 2012). Boylan and Syneos (2007) used he average
demand inerval, ha is he mean ime beween wo consecuive demands
greaer han zero, o classiy spare pars in conjuncion wih demand and lead-
ime uncerainy. Eaves and Kingsman (2004) developed similar conceps.
The model used by Yeh (1997) uses he probabiliy o no having a sock
shorage during an order cycle, ha is, during he inerval o ime beween
wo consecuive replenishmens, as a measure o he service level. The lowes
and highes desired service levels or each iem are defined according o he
model. The service level or he remaining sock is calculaed by 1-Ps(S), inwhich Ps(S), given in Appendix 4, is he probabiliy o sock shorage during he
order cycle, given he level o sock S.
. Mass consumption
Mass consumpion iems are requenly considered o be hose wih a
hisorical consumpion o over 300~500 unis per year, roughly one uni/day
(Wanke2005). According o Rosa e al. (2010), he classic lo size/reorder poin
model sands ou among mass consumpion iem invenory managemen
models. According o his model, unis are requesed whenever he sock
posiion reaches reorder poin (OP) (Love 1979; Silver e al. 1998; Mucksad
2004; Sherbrooke 2004; Hopp and Spearman 2008). In pracice, he size o loQis deermined by he radiional Economic Order Quaniy ormula (Harris
1913) and he reorder poin is defined so as o assure a specific service level
measure (Eppen and Marin 1988; Rego e al. 2011).
I is necessary o know he orma o he disribuion o lead-ime demand
o deermine he saey sock embedded wihin he reorder poin (Keaon
1995). According o Porras and Decker (2008), his calculaion requires
speciying he disribuion o lead-ime demand so ha he saey acor, K,
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL12
can be deermined. Tradiionally, lead-ime demand is modeled using a Normal
disribuion (Silver and Peerson 1985). Due o he properies o his disribuion,
he saey acor Kor a specific service level is he same as o he sandard
normal disribuion curve, Z, which can be ound in several saisics and
logisics exbooks such as, or example, Levine e al. (2005) and Ballou (2006).
Various sudies, however, criicize his approximaion. According o Menzer
and Krishnan (1988), his approximaion is only valid i he Normal disribuion is
defined beween he inerval o -and +. Moreover, his creaes he possibiliy
o negaive demand in many pracical applicaions. For Moors and Srbosch
(2002), one o he main drawbacks o he Normal disribuion is he symmery
assumpion. Furhermore, according o Eppen and Marin (1988), iems ha
presen a Normal disribuion o lead-ime demand are ound in only a ew cases.
As an atemp o balance he advanages and disadvanages o choosing an
specific premise, Silver e al. (1998) propose a general rule or approximaing
lead-ime demand using he probabiliy disribuion o he coefficien o
variaion (CV), in he specific case o mass consumpion iems. I CVis greaer
han 0.5, he Gamma disribuion should be used and, i i is no, a Normal
disribuion provides a good approximaion or lead-ime demand.
. CONCEPTUAL FRAMEWORK FOR INVENTORY MANAGEMENT
Taking he heoreical ramework presened in previous secions as a poin o
deparure, he presen aricle proposes a concepual ramework or invenory
managemen based on he segmenaion o annual demand ino hreecaegories very low consumpion, low consumpion and mass consumpion
and he coefficien o he variaion o demand ino wo caegories high
uncerainy and low uncerainy. Using hese wo demand patern-associaed
variables, he concepual ramework indicaes he mos appropriae invenory
managemen model or low, very low, and mass consumpion iems, hus supporing
decision-making based on he mos adheren premises o answer he quesions o
how much o order, when o order and how much sock o keep in saey socks.
In he concepual ramework synhesized in figure 1, exremely low
consumpion iems are considered o be hose wih an average hisorical
demand o less han one uni per year. Low consumpion iems correspond oiems whose average hisorical demand may vary beween one and 300~500
unis per year, or a maximum o one uni per day, while mass consumpion
iems are hose wih a demand o over approximaely 300~500 unis per year,
in accordance wih Wanke (2005). The cu-off poin or he coefficien o he
variaion o demand is 0.5, like in Silver e al. (1998).
More specifically, or each quadran o annual demand and he iems
coefficien o variaion o demand, he concepual ramework conains he
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VOLUME 49, NO. 1 1
mos adheren probabiliy disribuion uncions and he mos appropriae
invenory managemen model, incorporaing all he heoreical consideraions
described in he previous secions.
FIGURE : CONCEPTUAL FRAMEWORK FOR INVENTORYMANAGEMENT
In addiion o he developmen o concepual rameworks, Rego e al.
(2011) sress he need o conduc case sudies ocusing on heir pracical
applicabiliy in firms in order o overcome gaps beween heory and pracice.
These case sudies enable researchers o increase heir pracical knowledge
given ha aspecs involving undersanding abou environmens complexiy and
he managerial effors made by firms become eviden. Examples can be ound in
Cohen e al. (1990), Boter and Foruin (2000), Srbosch, Heus, and Schoo (2000),
Trimp e al.(2004), Levn and Segersed (2004), Wanke (2005), Porras and Dekker
(2008), Wagner and Lindemann (2008), Syneos, Keyes, and Babai (2009), and
Silva (2009). The ollowing secions presen and discuss he resuls o he pracicalapplicaion o he proposed concepual ramework in a large Brazilian company.
. PRACTICAL APPLICATION: DESCRIPTION OF RESULTS
The concepual ramework presened in secion 3 ormed he basis or he
developmen o a VBA ool or Excel o help segmen invenory iems using a
daabase srucured in an elecronic spreadshee. In addiion, his ool makes
i possible o obain a quick answer o he quesions o how much o order,
when o order and how much sock o keep in a saey sock or a large number
BinaryModels(Zero
orOne)
Coefficientofvariation
ofdemand
Lessthan
0.5
Great
erthan
0.5
Annual Demand0 1 300~500 Infiniy
Policy (Q, OP)
Order Poin
SS Gamma Disribuion
or Daa Hisogram
Order Poin
SS Normal Disribuion
or Daa Hisogram
Policy (S, S-1)
Shor Lead Time Lo = 1
Lead Time Long
Lo=Consunpion
Forecase during Lead Time
.Premises/Assumpions o
Deermine S:
Poisson
If 0,9 E(D) < Var (D) < 1.1 E(D)
Gamma
If he percenage of periods
during which D=0 exceeds
30% of he oal
Demand LT
Replenishmen LT
Average Demand
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL14
o iems, considering a given level o service ha he firm wishes o offer
cusomers and he previously idenified segmenaion. The ool was applied o
real daa rom a Brazilian company in order o measure possible gains resuling
rom he proposed concepual ramework or invenory managemen.
The firm ha was he objec o his pracical applicaion is one o he worlds
leading manuacurers o agriculural and consrucion equipmen. I has
approximaely one hundred sixy acories worldwide, o which hree are
locaed in Brazil. The Brazilian subsidiary has more han wo housand
employees. In addiion, he firm mainains a oal o more han 20,833 differen
iems in is Brazilian subsidiarys warehouses. The firm considers ha his
diversiy o iems is undamenal or providing suppor or echnical assisance
aciviies and pos-sales services or he equipmen i commercializes.
In order o perorm a comparison beween he invenory managemen acually
verified in he firm and he policy suggesed by he ool (concepual ramework),
he sudy used consumpion daa o he previous ory-eigh monhs or all
20,833 iems. Besides consumpion daa, oher daa inormed by he firm,
which was imporan or modeling purposes, was also used: iems acquisiion
cos; replenishmen/order placemen cos; unavailabiliy and penaly coss;
average supplier lead ime; variance o supplier lead ime; opporuniy cos o
mainaining socks or a year, or each o he differen iems.
The firs sep in he applicaion o he concepual ramework was o use he
Excel ool o segmen he iems according o he classificaion caegorieso very low consumpion, low consumpion and mass consumpion, which
resuled in he ollowing respecive percenages: 22 percen; 74.5 percen
and 3.5 percen. In addiion, based on he hree demand caegories and he
wo coefficiens o variaion, an analysis was underaken o demands degree
o adherence o he Poisson and Gamma disribuions, according o he
discussion presened in secions 2.2.1 and 2.2.2.
Figure 2 shows one o he ool s oupu screens conaining a sample o he
firs en iems analyzed, heir respecive classificaion (very low consumpion,
low consumpion and massconsumpion) and heir adherence o he mos
adequae probabiliy disribuion (Poisson or Gamma). I should be highlighedha, as he adherence o demand o he Poisson or Gamma disribuion was
no verified, i was assumed ha demand adhered o a Normal disribuion in
cases in which he coefficien o variaion was lower han 0.5.
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VOLUME 49, NO. 1 1
All he analyses presened below relae o very low and low consumpion iems
which represen 96.5 percen o oal iems.
As regards very low consumpion iems, i was observed ha, in he case o 99.9
percen o he iems classified in his group, he firm should keep a par in sock,
oaling 4,586 socked iems (one or each iem). The invesmen needed o orm
his sock exceeds BRL$2,540,000, i all pars have o be purchased iniially a he
same ime, hus generaing an annual opporuniy cos o over BRL$563,000.
In he case o low consumpion iems ha adhere o he Poisson or Gamma
disribuions, he sudy calculaed he levels o sock needed o caer o hreedifferen service levels: a niny percen, niny-five percen, and niny-eigh
percen probabiliy o no having a shorage o he iem in sock. For each level
o service he sudy calculaed he opporuniy coss o keeping he pars in
sock, as well he invesmen needed o purchase hese iems i hey iniially
had o be purchased simulaneously.
Specifically or he niny percen level o service, an invesmen o over
BRL$84,000,000 would be needed o orm his sock i all pars iniially had o be
FIGURE : RESULTS OUTPUT SCREENSEGMENTATION ANDADHERENCE TO THE DISTRIBUTION
ID Item Code Classification Poisson Gama
1 A1304031 Low Turnover no yes
2 A162896 Very Low Turnover no no
3 BNHCMP0001 Low Turnover no yes
4 BNHCMP0002 Mass Consumpion no no
5 BNHCMP0005 Mass Consumpion no no
6 BNHCMP0007 Mass Consumpion no no
7 BNHC0001 Low Turnover no yes
8 BNHC0002 Low Turnover no yes
9 BNHC0003 Low Turnover no yes
10 BNHC0004 Mass Consumpion no no
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL16
purchased simulaneously. This amoun involves an annual opporuniy cos o
BRL$18,670,000.00. This opporuniy cos o roughly weny-wo percen per year
is basically financial: i relaes o he high ineres raes o he Brazilian economy.
By he ime he case sudy was conduced (2010), he Brazilian base ineres
rae, named SELIC, was around welve percen per year. These addiional en
percen poins consiue he average spreads incurred by large companies when
borrowing money o suppor working capial requiremens, such as invenories.
On average, en pars are kep in sock or each low consumpion iem.
. PRACTICAL APPLICATION: DISCUSSION OF RESULTS
As he company did no divulge is real invenory policy nor wheher radiional
invenory classificaion schemes, such as ABC, subsidized decision-making
wih respec o invenory model segmenaion, he sudy made some working
assumpions in order o be able o evaluae wheher gains would occur in
boh financial and service level erms i he invenory models suggesed by
he concepual ramework were adoped. Some o hese working assumpions
considered he Normal disribuion alogeher wih (S, s)invenory model and
coninuous review or low and very low consumpion iems.
For very low consumpion iems, he sudy analyzed he impac, in erms o
oal coss, o keeping no (CT0) or one (CT1) par in sock, as shown by eqs. (A1)
and (A3), respecively. The resuls showed ha he mos appropriae policy was
o keep a par corresponding o each iem in sock as i led o a gain given
by he sum o he differences (CT0-CT1) or all iems o BRL$14,429,517.56.The gains ha can be achieved by keeping a par in sock or all iems are due
mainly o he high unavailabiliy and penaly coss, which hus consiue an
exremely imporan par o he cos difference beween he wo policies.
In he case o low consumpion iems, which represen 74.5 percen o he oal,
he sudy considered ha he arge-sock S or each iem was equal o he
mean o he hree bigges demand spikes ha had occurred during he previous
ory-eigh monhs. This is a common pracice wihin Brazilian companies
(c. case sudy in Wanke 2011). Then, or each iem, he sudy calculaed he
opporuniy cos or he level o sock suggesed by he ool and he one
effecively praciced by he firm. When he resuling difference was posiive,
i was considered ha he adopion o he concepual ramework would leado a reducion in opporuniy coss. In his case, his amouned o nearly
BRL$8,870,000, due o lower levels o invenory. Similarly, when he difference
was negaive, he sudy assumed ha here would be an increase in opporuniy
coss due o he rameworks adopion which, in his case, oaled nearly
BRL$2,230,000, on accoun o higher levels o invenory. I should be poined ou
ha, on mos occasions, he increase in invenory levels can be atribued o he
need o adjus cusomer service levels, sipulaed, in his case, a niny percen.
Wih he aim o ideni ying he oal ime aken o achieve financial gains
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VOLUME 49, NO. 1 1
resuling rom invenory demobilizaion, he sudy esimaed he amoun
o ime needed o consume excess invenory, based on average monhly
consumpion figures. The BRL$8,870,000 reducion in opporuniy coss is
achieved wihin a maximum imescale o 20.57 monhs, bu in a maximum o
six monhs i is possible o atain BRL$8,446,990.04, or 97.01 percen o he
oal, and in a litle under a year, more precisely in 10.29 monhs, i is possible
o achieve 97.89 percen o gains, amouning o BRL$8,676,001.41 (figure 3).
The ool, which idenified he adherence o he disribuions o low urnover iems o
he Poisson and Gamma disribuions, showed grea efficiency, producing savings o
BRL$2,321,674.55, o be achieved over a maximum period o 20.57 monhs.
FIGURE : Reduction Of The Opportunity Cost Of Maintaining
Stocks Over Time.
. CONCLUSIONS
A vas lieraure relaed o invenory heory has been developed over he pas
fify years. However, many o he heoreical resuls achieved are no easily
applicable in business pracice, given ha mos are based on premises ha
are no verified in he corporae environmen. Wih he aim o helping o fill
his gap, his sudy proposes a concepual ramework designed o suppor he
choice o he mos adequae/appropriae invenory managemen model.
Based on differen demand characerisics, he proposed concepualramework reveals ha he premise ha demand adheres o Normal
disribuion is no always valid and ha oher probabiliy disribuions, such as
he Poisson and Gamma disribuions, should be considered by managers. This
sudy also explored issues relaed o he managemen o socks o low and
very low consumpion iems hrough he rameworks pracical applicaion in a
Brazilian agriculural and consrucion equipmen company.
A
ccumulatedGain(BRLthousand)
Achievement Time (months)
0 5 10 15 20
2500
5000
7500
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL18
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APPENDIX DERIVATION FOR VERY LOWCONSUMPTION
ITEMS (TAVARES AND ALMEIDA )
The auhors demonsraed ha he oal cos associaed wih he policy o no
keeping a spare par in sock (CT0 ) can be calculaed as ollows:
(A1)
in which is he average hisorical consumpion (pars/year), CTR is he oal
cos o iem replenishmen/order placemen (BRL), and Cipis he cos o
unavailabiliy and penaly coss relaed o shorage (BRL).
In order o adop he alernaive policy, ha is, he firm keeps a uni in sockunil consumpion occurs, an evaluaion should be perormed o he expeced
racion o ime in sock (FTECE), given by:
(A2)
in which TRis he replenishmen lead-ime.
The expeced value o occurrences during he expeced racion o ime ou o
sock is given by *(1-FTECE). Thus, one can obain he oal cos associaed
wih he decision o always keep a par in sock (CT1 ), aking ino accoun he
possible occurrence o anoher reques during he lead ime, as well as is
implicaions in erms o replenishmen coss and unavailabiliy and penaly
coss, as given below:
(A3)
The pars o eq. (A3) represen, respecively, he opporuniy cos o keeping a
spare par in sock, he oal replenishmen cos and unavailabiliy and penaly
coss. In order o define he mos advanageous policy, i is necessary o
compare he magniudes o CT0 and CT1, oping or he leas-cos decision.
CT1= *Caq*i Cip**1+TR1 +[CTR*]+ 1+*TR
1
CT0=*(CTR+Cip),
FTECE= ,1+*TR
1
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL24
INTEGRATING FMEA WITH THE SUPPLY CHAIN
RISK MANAGEMENT PROCESS TO FACILITATE
SUPPLY CHAIN DESIGN DECISIONS
V. M. Rao Tummala
Computer Information Systems Department, College of Business, Eastern
Michigan University, Ypsilanti MI 48197
Tobias Schoenherr, CSCP (Corresponding Auhor)
Department of Supply Chain Management, Broad College of Business,
Michigan State University, East Lansing MI 48824
Thomas Harrison
Chief Executive Officer, Michigan Ladder Company, Ypsilanti MI 48198
ABSTRACT
We presen a novel approach o inegraing ailure mode and effec analysis
(FMEA) wih a supply chain risk managemen process (SCRMP). Focusing on
he challenging ask o assess and manage supply-side risks in global supply
chains, he approach developed offers an effecive and affordable way or
firms o provide decision suppor or he selecion o heir mos appropriae
supply chain design. The aim o he inegraed approach combining he
srenghs o FMEA and SCRMP is o gaher as much perinen inormaionas possible, o srucure i, and o comprehensively delineae all poenial
supply chain risk acors, offering valuable decision suppor. We illusrae
he applicaion o he approach a Michigan Ladder Company, where i was
applied o wo specific supply chains or he procuremen o fiberglass ladders.
Specifically, one supply chain spanned rom China o he U.S. via Mexico
(aking advanage o a Mexican maquiladora), and one spanned rom China
direcly o he U.S. The combinaion o FMEA and he SCRMP enhanced he
manuacurers confidence in is supply chain design decision, and enabled he
firm o proacively manage is supply-side risks. Overall, he aricle is mean o
moivae praciioners o embark on he journey o acive risk managemen.
While some may perceive risk managemen as a dauning ask or beingprimarily employed by larger firms, we provide guidance or firms o any size
o apply he approach i can be done, and does no have o consume an
inordinae amoun o resources.
Keywords: supply chain risk managemen, supply-side risks, ailure mode and
effec analysis (FMEA), supply chain managemen decisions, case sudy
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Introduction
Globalizaion has enabled companies o ake advanage o worldwide supply
and demand markes, creaing new opporuniies and increasing heir profi
poenial. However, wih hese enicing prospecs have also come he dangers
o associaed longer and more complex supply chains (Tang 2006), which ofen
span muliple counries or even coninens. Especially in a ime o increasing
cusomer demands and requiremens on qualiy, delivery lead ime and
responsiveness, managing hese global supply chains has become a challenge.
Ensuing risks are hus muliarious, and can manies hemselves in he orm
o supply disrupions or breakdowns (e.g., Hendricks and Singhal 2005; Sockes
2008; Tang and Musa 2011). This is especially heighened in imes o companies
ocusing on heir core compeencies, and ousourcing he remaining asks,
ineviabiliy increasing heir vulnerabiliy (Narasimhan and Talluri 2009).
Evidence is provided or example by he caasrophes associaed wih super-
sorm Sandy on he Eas Coas o he U.S. in 2012, he floods in Thailand in
2012, and he Japanese sunami in 2011. Besides he incomprehensible human
ragedies, he later even or example also resuled in companies such as
Apple, Sony Ericsson, and many auomobile manuacurers being unable o
quickly adjus heir supply chains; he firms were unable o compensae or he
missed supplies rom Japan, resuling in significan losses (BBC 2011). Furher
examples o imminen risks abound, such as he financial crisis affecing mos
companies and counries (Blome and Schoenherr 2011), as well as recen
poliical insabiliy and regime changes (Doukas e al. 2011).
Due o hese realiies, i has become an imperaive or odays supply chain
managers o ideniy possible risks affecing heir supply chains, evaluae
hem, and develop appropriae risk miigaion sraegies. However, his
underaking can be a dauning ask (Kwak and Soddard 2004), as was
revealed in a survey by Snell (2010): while 90 percen o he responding firms
el hreaened by supply chain risks, ew el confiden and knowledgeable
in managing hese risks. This finding is consisen wih our own anecdoal
observaions and recen ineracions wih supply chain proessionals. As such,
no many firms are employing a srucured approach o assess and manage
risks inheren in heir global supply chains, which is especially he case or
small- and medium-sized enerprises. This negligence can however havesevere repercussions, since even smaller firms and heir supply chains are now
ofen inerconneced globally and hus exposed o a muliude o risks.
I is hereore our objecive in he presen paper o illusrae a novel approach
combining ailure mode and effec analysis (FMEA) wih a supply chain risk
managemen process (SCRMP). This inegraed mehodology provides
guidance or managers on how o beter ge a handle on risks associaed
wih heir exising or poenial supply chain designs. The aim o he approach
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL26
combining he srenghs o FMEA and SCRMP is o gaher as much perinen
inormaion as possible, o srucure i, and o comprehensively delineae all
poenial supply chain risk acors. We illusrae his applicaion a Michigan
Ladder Company (MLC), which uilized he inegraive approach o provide
decision suppor or is supply chain design. The mehodology srucured
he decision problem and offered he firm more confidence in is final choice.
The approach was applied o assess he supply-side relaed risks inheren in
wo alernae supply chain designs or he procuremen o fiberglass ladders.
While one supply chain design involved he procuremen o he finished
produc rom China, he oher involved he procuremen o pars rom China,
assembling hem in a Mexican maquiladora, and hen shipping hem o he
U.S. locaion o MLC. The risks associaed wih each were assessed relaive
o he firms objecives o cos reducion and responsiveness. Wihin his
conex, supply chain risk was defined as he hrea or probabiliy o supply
chain disrupions ha adversely affec he smooh flow o producs, impacing
operaional perormance measures such as responsiveness and cos.
The developmen and illusraion o he approach is imporan boh rom
a pracical and a heoreical perspecive. From a pracical angle, he value
consiss o he presenaion o an effecive, comprehensive, and inegraed
ramework or risk managemen, consising o boh FMEA and he SCRMP,
as well as an illusraion o how i can be applied. The imporance inheren
in he later is he demonsraion ha risk managemen does no have o be
rocke science or hugely expensive, and ha sraighorward approachescan yield significan insigh. I is hus our hope ha he aricle provides an
impeus, moivaion and guidance or pracicing managers o ollow his
ramework, especially also or small- and medium-sized firms, which may have
been hesian o adop risk managemen approaches in he pas due o heir
poenial associaed expenses and effor. We are also direcly addressing
a shorcoming menioned in Snell (2010), who ound in heir survey ha
respondens did no eel confiden and knowledgeable in managing hese
risks. The approach presened herein is a means o increase confidence and
knowledge in risk managemen, and represens a ready-o-use ool o beter
manage global supply chain risks.
The sudy also conribues o lieraure and heory in supply chain risk
managemen in ha i proacively idenifies and evaluaes risk and miigaion
sraegies, insead o examining ex pos scenarios (c. Trkman and McCormack
2009); his leads o he urher improvemen o he firms confidence in is
supply chain design ex ane, anicipaing poenial ailures and developing
prevenive and response acion plans. The successul experiences made by
Michigan Ladder Company demonsrae he useulness o he approach and
is significan poenial in aciliaing supply chain decisions ocusing on risk
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VOLUME 49, NO. 1 2
assessmen and managemen. We hus also answer he call or urher insigh
ino risk managemen approaches o aciliae and srucure supply managers
sraegic decision making on he opimal configuraion o heir supply chains
(Zsidisin e al. 2004). In addiion, we ollow he example o Chan e al. (2012),
who encouraged he inegraion o FMEA wih risk analysis approaches. As
such, overall, we make imporan conribuions o boh pracice and heory/
lieraure in producion and operaions managemen.
The nex secion provides a brie inroducion ino he general area o supply chain
risk managemen. This is ollowed by a descripion o he inegraive approach
combining FMEA and he SCRMP. Michigan Ladder Company and he conex in
which he approach was implemened are presened nex. This is ollowed by he
applicaion o our suggesed approach a MLC. The ensuing secion discusses he
resuls, illusraes he derived value or MLC, and describes he acions resuling
rom he approach. A las secion concludes he aricle.
Supply Chain Risk Management
We define supply chain risk as he hrea or probabiliy o supply chain
disrupions ha adversely affec he smooh flow o producs, impacing
operaional perormance measures such as responsiveness and cos.
This definiion was derived rom exan lieraure, bu was also specifically
influenced by he conex o MLC and how i viewed supply chain risk.
Mos definiions ound in lieraure go back o he concepualizaion offered
by he Briish Sandards Insiue, which described risk as a combinaion oprobabiliy or requency o occurrence o a defined hazard and magniude o
occurrence (BS 4778, 1991). O paricular relevance in he presen sudy is he
risk o inerruped supply. Wihin his conex, supply risk has been defined
as ailures associaed wih inbound goods and services ha affec he firm
o mee cusomer demand (Zsidisin e al. 2004, 2005). Similarly, Harland e
al. (2003), reerring o Meulbrook (2000), described supply risk as adversely
affecing inward flow o any resource ha hinders scheduled operaions. Our
concepualizaion is in line wih hese prior definiions.
The criicaliy o ensuring he smooh flow o producs hrough he supply
chain and he impac o supply chain disrupions has been highlighed byrecen evens. For example, supply chains have been impaced by naural
disasers, such as he super-sorm Sandy on he U.S. Eas Coas in 2012, floods
in Thailand in 2012, he Japanese sunami in 2011 (Dawson 2011), he 2006
earhquake in Java, he hurricanes Karina and Ria in 2005 (Devlin 2005), and
he ongoing hackings o vessels by piraes off he coas o Somalia (Bowman
2010). The immediae impac o announcemens concerning such supply
chain disrupions on shareholder value has been shown by Hendricks and
Singhal (2005). I is hereore crucial or managers o ideniy and undersand
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL28
he associaed risks wih heir supply chains, as well as o hen develop risk-
reducion sraegies (Chopra and Sodhi 2004).
Responding o hese realiies, academic research ino supply chain risk
managemen has flourished. For example, Waers (2011) ocused on supply
chain risk managemen rom he perspecive o logisics, and Sodhi and
Tang (2012) called or companies o more proacively manage he associaed
risks. Frsl e al. (2011) repored on wha represens excellence in supply
risk managemen across differen indusry secors, and Olson (2012) offered
analysis ools or supply chain risk managemen. Allen and Schuser (2000)
examined risk managemen a Welchs, Inc., or heir harvesing o grapes,
and Maneti (2001) emphasized he imporance o r isk managemen or
he choice and implemenaion o echnologies in manuacuring. Risk
managemen was described as an essenial ingredien or projec planning
by De Reyck (2010). Pohl e al. (2010) summarized exan lieraure in supply
chain risk managemen, complemening earlier work by Tang (2006) who
ocused on he review o quaniaive models or he managemen o supply
chain risk. A review o recen sudies in supply risk is also provided in Blome
and Schoenherr (2011).
Various approaches have been suggesed or he managemen and miigaion
o supply chain risks. As such, Kilgore (2004) inroduced an analyical
risk miigaion ramework consising o five seps, Giannakis and Louis
(2011) proposed a muli-agen decision suppor sysem or supply chainrisk managemen, and Wagner and Nesha (2010) assessed supply chain
vulnerabiliy using graph heory. De Waar (2006) developed an inormal
assessmen ool o implemen risk miigaion sraegies, Sheffi and Rice
(2005) used he dimensions o disrupion probabiliy and consequences
as caegorizaion scheme, and Kleindorer and Saad (2005) proposed a
ramework reflecing he aciviies o risk assessmen and risk miigaion.
Sinha e al. (2004) suggesed a prescripive risk mehodology applied o
he aerospace supply chain, Cucchiella and Gasaldi (2006) proposed a real
opions-based supply chain risk managemen approach, and Huhn and Kahn
(2012) uilized robus opimizaion o manage supply chain risks. We build
on and exend his sream o research and propose a novel and innovaivesupply chain risk managemen approach, which will be described nex.
FMEA and SCRMP
In our inegraed approach we combine he srenghs o radiional FMEA
(1995), and uilize i ogeher wih specific echniques such as he U.S. Miliary
Sandard 882C and he Hazard Toem Pole (Grose 1987), as par o he SCRMP.
Wihin his conex, FMEA enables he assessmen o poenial ailures and
heir effecs, ogeher wih he developmen o prevenive acion plans and
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VOLUME 49, NO. 1 2
associaed implemenaion coss, effecively complemening he SCRMP.
A recen sudy illusraed he power o inegraing FMEA wih general risk
managemen approaches, noed he dearh o research in his area, and
hus called or he urher invesigaion o his area (Chan e al. 2011). Chan
e al. (2011) specifically noed ha here is a lack o pracical guidance in he
inegraion o risk and ailure analysis, and sressed he significan poenial o
doing so. We answer his call in he presen sudy.
The value o inegraing FMEA wih oher approaches can be considerable,
given exan research ha repored on such inegraion effors. For example,
Shahin (2004) inegraed FMEA wih he Kano model, Chang and Paul (2009)
combined FMEA wih daa envelopmen analysis, and Chin e al. (2009)
inegraed i wih he evidenial reasoning approach. In he presen sudy, we
inegrae FMEA wih he supply chain risk managemen process and illusrae
is combined applicaion.
Failure Mode and Effect Analysis (FMEA)
Failure mode and effec analysis (FMEA) is a srucured approach o ideniy
and preven produc and process ailures beore hey occur (McDermot e
al. 2009). Having evolved rom firs applicaions in he aerospace indusry in
he 1960s, i has since hen been widely employed or produc and process
improvemen effors and or he purpose o reducing he risk o ailures
(Samais 2003). In FMEA, every possible maluncion or breakdown is
assessed in erms o he poenial causes o he ailure, he poenial effecsand consequences, prevenive acions possible, and coss o hese prevenive
acions (Taikonda and Taikonda 1994). FMEA has been applied or example
o projec risk managemen (Tummala and Mak 2001; Ng e al. 2003; Carbone
and Tippe 2004) and o he implemenaion o enerprise resource planning
sysems (Shirouyehzad e al. 2011). I was also noed ha benefis rom FMEA
are mos ully realized i i is par o a qualiy managemen sysem (McDermot
e al. 2009). Exending his idea, we orward he noion ha he applicaion o
FMEA ogeher wih he SCRMP is mos effecive.
While mos FMEA sudies have ocused on produc and manuacuring
process improvemens, and no on supply chain managemen, he inherenineres o hese prior sudies was in reducing he risk o produc or process
ailures (Samais 2003). Wha is hereore imminen is he applicabiliy o
supply chain risk managemen. Wih a ew excepions, however, exan
research has no deal wih he applicaion o FMEA o supply chain risk
managemen, an observaion which suggess o have lef many opporuniies
on he able. Wihin he conex o supply chain managemen, Elkins e al.
(2005) proposed using FMEA o race back he roo cause o a ailure and learn
rom he even, and Teng e al. (2006) provided guidance or implemening
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL30
FMEA in a collaboraive supply chain environmen. We exend hese works by
illusraing he combined applicaion o FMEA wih he SCRMP.
Supply Chain Risk Management Process (SCRMP)
The Supply Chain Risk Managemen Process (SCRMP) is a ramework or he
assessmen o he risk profile associaed wih a specific supply chain, and
was concepually developed by Tummala and Schoenherr (2011). I offered
a pracical emplae o manage supply chain risks more effecively in a
srucured ashion. However, he auhors ailed o illusrae he approach
in he real world, quesioning is applicabiliy and relevance or managerial
pracice. In he curren research, we work owards alleviaing his omission,
and inegrae i wih FMEA.
The core o he SCRMP consiss o hree phases: (I) risk idenificaion, risk
measuremen and risk assessmen, (II) risk evaluaion, risk miigaion and
he developmen o coningency plans, and (III) risk conrol and monioring
(Tummala and Schoenherr 2011). The purpose o phase I is o enumerae all
possible poenial supply chain risks, and assess heir severiy and likelihood o
occurrence. Phase II evaluaes he idenified risks o develop appropriae risk
response sraegies or risk reducion and managemen. Phase III develops a
risk-based daa managemen and analysis sysem o monior he effeciveness
o he implemened risk reducion plans.
In he curren sudy we ocus on phases I and II o he SCRMP, heir inherenprocess seps, associaed echniques and evaluaion approaches. Specifically,
he seven process seps ha we consider are he ollowing: (1) ideniy
poenial supply chain risk acors; (2) assess he severiy o consequences
o he idenified risk acors; (3) assess he likelihood o occurrence o he
idenified risk acors; (4) classiy he idenified risk acors; (5) deermine he
cos o implemening risk response acion plans; (6) deermine risk prioriy
scores; and (7) consruc he Hazard Toem Pole char. The las phase and
remaining process seps no considered reer o acions aken afer he risk
miigaion and coningency plans have been implemened, and deal wih
ongoing risk conrol and monioring. These seps are no considered since
hey are ouside o he scope peraining o he inegraion o FMEA; raher,hey uilize resuls o he prior seps and FMEA o effecively manage risk.
CONTEXT AND BACKGROUND
We illusrae he applicaion o our approach a Michigan Ladder Company
(MLC), a small manuacurer and disribuor o ladders, locaed in Ypsilani,
Michigan. The produc specrum o MLC is narrow bu deep, including
aluminum, fiberglass and wood ladders. The firm has been enjoying good
financial healh despie he economic downurn, providing evidence o is
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VOLUME 49, NO. 1 3
sound risk managemen approaches. Esablished in 1901, MLC is he oldes
U.S. ladder manuacuring company, supplying ladders primarily or he
commercial secor, including he miliary. The coninued success o he
company is atribued o is innovaive and loyal workorce, as well as MLCs
emphasis on and dedicaion o qualiy producs. The firm was chosen o serve
as an exemplar or he applicaion o our approach, since i had been very
proacive in is houghs oward risk managemen.
An earlier approach o risk managemen ha he company was aking,
involving he analyic hierarchy process (AHP), was chronicled in Schoenherr
e al. (2008). This evaluaion was riggered by changes in he compeiive
landscape and he wish o move he sourcing o wo o he firms major
produc lines rom a Mexican supplier o an alernae source. The five
alernaives considered were (1) he sourcing o finished goods rom Mexico, (2)
he sourcing o finished goods rom China, (3) he sourcing o pars rom China
and assembly in he U.S., (4) he sourcing o pars rom China, assembling
hem in a maquiladora in Mexico wih invesmen, and (5) he sourcing o
pars rom China, assembling hem in a maquiladora in Mexico wih no
invesmen. These supply chain designs and associaed sourcing locaions
were considered due o heir appeal in erms o boh qualiy and cos, which all
alernaives demonsraed. A oal o seveneen risk acors were idenified as
being relevan or he firm. Using AHP modeling, he risk acors were assessed
across he five alernaives, yielding a preerence score minimizing he risks
or each alernaive. As a resul, he hree alernaives wih he leas risk wereimplemened (alernaives (2), (5) and (1)). Three supply chain designs were
pursued, so as o urher diversiy he risk inheren in each. This approach
has been receiving grea ineres by praciioners, and was also eaured
a a dinner presenaion held or he Greaer Deroi Chaper o APICS. We
hereore conaced MLC o solici is paricipaion or he presen sudy.
Due o he dynamic environmen, MLC was consanly re-evaluaing is
sraegic choices regarding is ousourcing aciviies. A he ime he sudy
was conduced, he company had abandoned alernaive (1), which was merely
reained unil he new supply chain designs were ully operaional. As such,
he company was operaing wih wo supply chain designs: (A) he sourcingo finished goods rom China, and (B) he sourcing o pars rom China,
assembling hem in a Mexican maquiladora (wih no invesmen aken in he
venure), and hen shipping hem o he Midwes locaion o he firm. We will
reer o opion (A) as he China-Midwes supply chain, whereas opion (B) is
reerred o as he China-Mexico-Midwes supply chain.
Alhough hese wo supply chains represened he leas risk, based on he
prior AHP analysis, qualiy problems began o emerge abou a year afer he
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL32
commimen o he China-Midwes supply chain had been made. A more
deailed invesigaion o he risk acors involved in his supply chain was
hereore needed, offering a ormidable conex o apply FMEA inegraed
wih he SCRMP. In order o provide a comparison benchmark, i was
decided o also include he second leas-risky alernaive in he evaluaion,
he China-Mexico-Midwes supply chain, which had also been in operaion.
The design, srucure and configuraion o hese wo supply chains is quie
diverse, involving a differen se o supply chain risks and differing inensiy
levels or each. As such, a more rigorous assessmen o hese wo scenarios
was now warraned. In addiion, in conras o he earlier evaluaions via AHP,
he wo supply chains were now ully operaional, and acual experiences
had been made o beter gauge he risks. Thereore, in collaboraion wih he
company, he approach presened herein was developed, combining FMEA
and he SCRMP. The goal was o aciliae he decision on he opimal supply
chain design, minimizing supply-side relaed risks. The overriding objecives
o he assessmen were o reduce coss along he supply chain, wih
however a he same ime improving (or a leas no deerioraing) service
levels and responsiveness.
Differentiation to Prior Work
The curren work builds on and exends prior sudies, and we would like o
highligh how he curren paper differeniaes isel. Specifically, above we
noed ha we are ollowing up on a decision Michigan Ladder Company had
made peraining o five offshoring alernaives, which was aciliaed wihhe Analyic Hierarchy Process and presened in Schoenherr e al. (2008).
Our work differeniaes isel in ha we are no relying on AHP o offer
decision suppor. While we conduced our research a he same company
wih he same risk acors (since hese risk acors were sill deemed valid by
he company), he ramework presened in he presen paper is differen in
ha we apply a novel approach inegraing FMEA and he SCRMP.
In addiion, he presen paper describes an approach or decision suppor
ha was aken laer on in he imeline o he company, once he decision
chronicled in Schoenherr e al. (2008) had been made. As such, we are
ocusing on he wo leas risky alernaives idenified in Schoenherr e al.(2008) , and provide more enhanced and deailed decision suppor, building
on and exending his prior work. Furhermore, we base he assessmen
on he acual operaion o he wo supply chains, or boh o which
experiences had now been made. Moreover, even hough we consider
he same seveneen risk acors as hose idenified by Schoenherr e al.
(2008) , he use o FMEA and he applicaion o he principles inheren in he
SCRMP, such as he U.S . Miliary Sandard 882C and he Hazard Toem Pole,
enabled us o provide a much more deailed analysis o assess he poenial
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL34
INTEGRATING FMEA WITH THE SCRMP: AN APPLICATION AT MLC
This secion describes he inegraion o FMEA wih he SCRMP, as well as how
i was applied a MLC. Table 1 provides a summary o his inegraion. Overall,
his expos provides a valuable applicaion and emplae or oher firms acing
similar problem scenarios and decisions.
TABLE :INTEGRATION OF SCRMP AND FMEA
Step Step in the SCRMP Integration with FMEA
1 Idenify risk facors
Define he poenial failure mode (i.e. how he specific risk manifess
iself in erms of failures or breakdowns for MLC), poenial causes of
he failure or breakdown, poenial effecs or consequences of he
failure or breakdown, prevenive acions ha could be done, and he
cos of such acions
2 Assess he severiies of consequencesUpdae (add or modify) he FMEA framework by more deailed
informaion having emerged hrough his SCRMP sep
3 Assess he likelihood of occurrenceRefer o informaion colleced in he FMEA o make more informed
decisions on he assignmen of individual likelihood values
4 Classify he idenified risk facorsRefer o informaion colleced in he FMEA o subsaniae
classificaion; if necessary, make adjusmens o beter reflec realiy
5Deermine he cos of implemening risk
response acion plans
Provide more deail in he FMEA framework peraining o specific
coss, as well as subsaniaion for specific cos esimaes
6 Deermine risk prioriy scores
Subsaniae he classificaion ino risk prioriy scores wih
qualiaive informaion recorded in he FMEA, combining he
srenghs of boh approaches
7 Consruc he Hazard Toem Pole char
Uilize informaion from he FMEA framework o subsaniae
classificaions and overall srucure of he Hazard Toem Pole, refuing
he criicism ha SCRMP scores can be subjecive; his can be
especially useful in he presenaion o ohers affeced by he decision
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VOLUME 49, NO. 1 3
Step 1: Identify Risk Factors
We commenced wih he firs sep o he SCRMP, i.e. he idenificaion o
supply chain managemen risk acors. Useul approaches a his sage
include brainsorming or he nominal group echnique. All easible risks should
be idenified ha could poenially influence he desired oucomes. The
overriding objecives o he risk assessmen in he case o MLC were o reduce
coss along he supply chain, wih however a he same ime improving (or a
leas no deerioraing) service levels and responsiveness. These objecives
were kep in mind when considering poenial supply-side risk acors or MLC.
Afer a review o poenial risks, he research eam deemed he seveneen
risk acors as idenified earlier (Schoenherr e al. 2008) as sill represening
he curren siuaion. Furher discussions and eedback obained rom
colleagues no involved in he research and in oher uncions did no lead o
any addiional applicable acors. These seveneen risk acors, as well as heir
definiions and corresponding abbreviaions used in he ensuing discussion,
are summarized in Table 2.
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PRODUCTION AND INVENTORY MANAGEMENT JOURNAL36
TABLE :IDENTIFIED RISK FACTORS
Risk
Factor
Code
Risk Factors Label Risk Factor Definitions
ACR ANSI ComplianceMinimum requiremens ha he companys producs mus a leas fulfill, and he risk ha he
supplier fails o mee hese requiremens.
PQR Produc QualiyLikelihood of he supplier no providing an excellen produc in erms of qualiy (measured in
erms of he number of defecive producs).
PCR Produc Cos Price ha he company pays for he produc, and he risk associaed wih a price increase.
CCR Compeior Cos
A measure of how he price ha he company receives from is suppliers compares o he price
compeiors are likely o pay for comparable inpu. I represens he risk of he compeior having a
relaive cos advanage.
DMR Demand RiskMeasures he likelihood of severe swings in demand, and he responsiveness he respecive
supply chain would exhibi in accommodaing hese swings.
SFR SupplierFulfillmen Risk
Esimaes how accurae suppliers are fulfilling he orders, boh in erms of qualiy, quaniyand puncualiy.
LGR Logisics RiskRisks due o organizaional aspecs of logisics, such as paperwork involved, scheduling roues,
deermining wha o ship wih wha mode and a wha ime, selecion of pors and carriers, ec.
TBROn-Time and
On-Budge Risk
Deals direcly wih he abiliy of he supplier o deliver he produc o he company on-ime
and on-budge, i.e. wihou delays and wihou any higher coss.
OFROrder Fulfillmen
Risk Addresses he risk ha producs ordered are no delivered in he quaniy and qualiy demanded.
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WPRWrong Parner
Risk
Risk of engaging wih he wrong parner, and hus, due o heir poenial poor performance,
no being able o mee cusomer needs and/or demand requiremens.
OSR Overseas RiskConsiders he possibiliy ha relaionships overseas are more difficul o manage, due o for
example culural and poliical facors, bu also disance and language barriers.
SUR Supplier RiskConcerned wih he chance ha he supplier goes ou of business / goes bankrup as a resul
of poor managemen capabiliy.
SSMSuppliers
Supplier Risk
Deals wih how he immediae (or Tier 1) supplier manages is sources of supply and he associaed risk,
i.e. he buying companys second and possibly also hird and fourh ier suppliers.
EIREngineering and
Innovaion Risk
Concerned wih he suppliers capabiliy o collaborae on design, he poenial for join
innovaions, as well as he poenial for he leakage of confidenial informaion shared.
TPR TransporaionRisk
Measures he exen o which carriers can have problems in he physical movemen of goods.
SVR Sovereign RiskAssesses he risk associaed wih giving up conrol when going overseas, including poenial
poliical insabiliy, srikes, and sringen governmen regulaions
NTRNaural Disasers/
TerrorismLikelihood ha he supply chain can fall vicim o naural disasers and errorism atacks.
Risk
Factor
Code
Risk Factors Label Risk Factor Definitions
TABLE :IDENTIFIED RISK FACTORS CONTINUED
Insrumenal a his sage, peraining o he inegraion o FMEA wih heSCRMP, was ha as much deail as possible or each risk acor was colleced.
The opporuniy o gaher his inormaion a his sage is given, since here
is usually an underlying raionale or a eam member o sugges a paricular
risk as being imporan. Specifically, or each idenified risk acor, we aimed o
define he poenial ailure mode (i.e. how he specific risk maniess isel in
erms o supply chain ailures or breakdowns or MLC), poenial causes o he
ailure or breakdown, poenial effecs or consequences, possible prevenive
acions, and he cos o such acion. These caegories were revised and/or
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complemened wih addiional inormaion ha was riggered in he ensuing
sages o he SCRMP. For example, or he on-ime and on-budge risk
(risk acor code TBR; his risk acor will be used as an illusraive example
hroughou), which addresses he abiliy o he supplier o deliver he produc
wihou delays and wihou any higher coss, he poenial ailure mode or MLC
was idenified as no having wha is needed and when i is needed. Poenial
causes were atribued o he lack o manuacuring capabiliy and ransporaion
flexibiliy on he par o he supplier. Effecs o his ailure were lower saey sock
levels, los sales, and higher replacemen coss. Prevenive acions ha were
idenified included a closer working relaionship wih logisics personnel and
suppliers, he provision o help o he supplier or improving heir processes and
capabiliies, and more effecive communicaion. The implemenaion o hese
iniiaives was esimaed o cos $60,000. The FMEA analysis or all risk acors
peraining o he China-Midwes supply chain is presened in Appendix A.
Step 2: Assess the Severities of Consequences
In he second sep o he SCRMP we uilized Miliary Sandard 882C (1993)
o define he caegories o consequence severiies ino caasrophic, criical,
marginal or negligible (yielding he Risk Consequence Index). The our-
level sandard was adaped o MLC in a cross-uncional ashion involving
he academics and he CEO o he company. As such, a caasrophic
consequence (risk severiy index = 4) was described as he plan being shu
down, equivalen also o no delivery occurring or more han one monh due
o lack o componens and zero saey sock levels. The consequence wasdescribed as criical (risk severiy index = 3) i he process slowed down or i
no delivery was received or more han one week due o lack o componens
and zero saey sock levels. A siuaion wih decreasing service levels and
depleing saey sock was described as marginal (risk severiy index = 2),
while an insance wih service levels no being impaced due o sufficien
saey sock levels was considered negligible (risk severiy index = 1). These
degrees o magniude can be adaped based on he individual companys
assessmen o wha would represen a caasrophic, criical, marginal or
negligible even; according o he miliary sandard, he wors possible even
is considered in each caegory. Wih hese definiions in place, we evaluaed
each o he seveneen risk acors along heir respecive consequence severiyon he objecives o (a) cos reducion and (b) responsiveness (service levels).
Since i was our inen o assess he curren offshoring sraegy