the crystal family of methodologies for software development

©Alistair Cockburn 2003-2005 Slide 1

Alistair Cockburnhttp://alistair.cockburn.us

The Crystal FamilyThe Crystal Familyof Methodologiesof Methodologies

for for Software DevelopmentSoftware Development


History 1991 - 2004

1991: Alistair Cockburn (pronounced Co-burn) wanted to develop an effective software development methodology.

He interviewed and studied project teams for 10 years.

He found that “people-centric methodologies” do better than “process-centric” methodologies.

He found that you must choose and tailor the methodology to the team and the assignment (cannot have 1 methodology design for all projects).

1994: “Orange” used on 45-person fixed-price project1997: “Orange” published in Surviving OO Projects1998: Family of methodologies the name “Crystal”2004: “Crystal Clear” published as book


What were the most common characteristics of successful projects?

• People sit close together• They communicate frequently and with good will• The eliminate bureaucracy and let them design• They get a real user directly involved• They have good automated regression tests• THey produce shippable functionality early and often

A good methodology (family) must prioritize for these!


‘Methodology’ is only the set of conventions people agree to follow -- it changes every few months!

As the people on the team change, the conventions of the team change, also.

As the project evolves from start to middle to end, the strategies and conventions change, also.

The methodology of the team needs to change along with the situation.

This is natural is we view the methodology only as the conventions the team uses, and nothing more!

(Most people try to use ‘methodology’ as required development technique and also project management -- this is too much burden to place on a methodology)


Crystal is the lightest, least intrusive set of rules that puts a project in the safety zone.

Crystal’s purpose: Keep people from hurting each other, keeping each other informed

Crystal’s nature: A set of conventions that gets updated

Crystal’s Philosophy: People differ in working styles Projects differ in needs Software development is communication-intensive,

experiment-based, needing lots of feedback in all directions Less is generally better (for methodologies) Techniques / technologies change over time People learn in class or on the job, not from the

methodology


Clear Yellow Orange Red

Crystal is a family of methodologies because every project is slightly different and needs its own.

Technologieschangetechniques.

Cultureschangenorms.

Distanceschangecommunication.

Number of people involved

C

riti

cali

ty(d

efec

ts c

ause

loss

of.

..)

Comfort(C)

Essentialmoney

(E)

Life(L)

1 - 6 - 20 - 40 - 100 - 200

C6 C20 C40 C100 C200

D6 D20 D40 D100 D200

E6 E20 E40 E100 E200

L6 L20 L40 L100 L200

Discretionarymoney

(D)


Crystal is a family of methodologies with a common genetic code.

1 Cooperative Game Mindset: SD is a series of resource-limited cooperative games of communication and invention.

2 Methodology Design Priorities: Project safetyDevelopment efficiencyHabitability (tolerates humans!)

3 Methodology Design Principles: (7 of them, including: face-to-face work, concurrent development, & different rules for different circumstances)

4 Project Properties: Frequent delivery Close communication Reflective Improvement

5 Techniques: Discretionary but with a starter set.

6 Sample Methodology Designs: Crystal Clear Crystal Orange Crystal Orange-web


1: Crystal’s 1: Crystal’s MindsetMindset

“Software development is a (resource-limited) finite, goal-seeking cooperative game

of invention and communication.”


InfiniteOrganization Survival

Career Management

A finite, goal-directed (resource-limited!)cooperative game

Competitive Cooperative

Finite w/no fixed end

Jazz musicKing-of-the-hill

wrestling

Finite & goal-directed

Tennis

SoftwareDevelopmen

tChess

Rock-Climbing

Games

Poker


The game has a primary and secondary goal: Two Games in One !

Primary Goal Deliver working software. (Mess up the first goal => no software.

Secondary Goal Set up for the next game. Mess up the secondary goal => disadvantaged next project


Plan-drivensweet spot

Time and Effort Invested in Plans

Da

ma

ge

fro

m

ov

er/

un

de

rpla

nn

ing

The “correct” mix of planning vs. agility depends on the individual project’s risk exposure.

from “Get Ready for Agile Methods – With Care” (Barry Boehm, IEEE Computer, January 2001)

Agilesweet spot


2: Crystal’s 2: Crystal’s Design PrioritiesDesign Priorities

•Project Safety•Development Efficiency

•Process Habitability


Richness (“temperature”) of communication channel “cold” “hot”

Com

mun

icat

ion

Eff

ecti

vene

ss

2 people atwhiteboard

2 people on phone

2 peopleon email

Videotape

PaperAudiotape

(No Question-Answer)

(Questio

n-and-Answer)

3: Crystal’s 3: Crystal’s Design PrinciplesDesign Principles


Seven principles for methodology design

1. Prefer face-to-face communication Interactive face-to-face communication is the cheapest and

fastest channel for exchanging information2. Methodology weight is costly3. Use heavier methodologies for larger / distributed teams4. Use More ceremony for more criticality5. Use more feedback & communications,

with fewer intermediate deliverables6. Discipline, skills, understanding counter

process, formality, documentation7. Efficiency is expendable at non-bottleneck activities.


Agile processes are easy to describe understand as nested cycles of different durations.

Project

Episode

Integration

Day/Week

Iteration

Delivery


To understand Crystal (or any agile process), describe each cycle independently.

Project

Delivery Delivery

IterationIteration

Iterations

Day/WeekIntegration Integration

Day/Week

Integrations

Days Days

Integrations

EpisodesEpisode Episode Episode Episode Episodes

Integrations

Episodes


The activities of any one day may belong to different cycles

Project Iteration Day Integration EpisodeCharter

Plan Daily standup

Design & Check-inDesign & Check-in

Build and testDesign & Check-inDesign & Check-in

Build and test Daily standup

Design & Check-inDesign & Check-in

Build and testDesign & Check-inDesign & Check-in

Build and testDeliverReflect and celebratePlan(etc.)

Wrapup


4: Crystal’s 4: Crystal’s Project PropertiesProject Properties

•Frequent Delivery•Osmotic Communication•Reflective Improvement•Personal Safety•Focus•Easy Access to Expert Users•Technical Environment with

- Frequent integration- Automated testing- Configuration management


5: Crystal’s 5: Crystal’s StarterStarter Strategies & TechniquesStrategies & Techniques

•Methodology Shaping•Reflection Workshop•Blitz Planning•Delphi Estimation•Daily Stand-ups•Agile Interaction Design•Process Miniature•Side-by-Side Programming•Burn Charts

•Exploratory 360°•Early Victory

•Walking Skeleton •Incremental Rearchitecture

•Information Radiators


Critical technique in Crystal:The reflection workshop each month or iteration.

Hang a 2-column flipchart

Fill in the chart (30 minutes)

Hang the chart in a public, visible, frequently seen place !

Try the ideas

Repeat each month or after each iteration

Keep these Try these

Problems

test lock-downquiet timedaily meetings

pair testingfines for interruptions

programmers help testers

too many interruptionsshipping buggy code


6: Crystal 6: Crystal Sample Sample MethodologyDesignsMethodologyDesigns

Crystal Orange Crystal Orange/web Crystal Clear


Crystal Orange : scopeFor D40 projects:

Up to 40 people, same buildingLoss of discretionary moneys (May extend to E50)

Not for very large projects (insufficient subteaming)

Not for life-critical projects(insufficient verification)

(Described in Surviving OO Projects, Cockburn, 1998, pp. 77-93)

AmberC6 C20 C40 C80

D6 D20 D40 D80

E6 E20 E40 E80

L6 L20 L40 L80


Crystal Orange roles & teams for 45 people

Roles:

Sponsor, Business expert, Usage expert, Technical facilitator, Business analyst/designer, Project Manager, Architect, Lead designer/programmer, Designer/programmer, UI designer,Design Mentor, Reuse Point, Writer, Tester

Teams: System planning, Project monitoring, Architecture, Technology, Functions, Infrastructure, External test.


C6 C10

D6 D10

E6 E10

Crystal Clear : scope

For D6 projects:3-6 people, close or in same roomLoss of discretionary moneys (may extend to: E8 project)

Not for large projects (insufficient group coordination)

Not for life-critical projects(insufficient verification)

(Described in Crystal Clear, Cockburn, 2004also in Agile Software Development, Cockburn 2002)


Crystal Clear roles & teams for 3-8 people

Required Roles:

sponsor, senior designer, designer/programmer, user (part-time)

Combined Roles:

coordinator, business expert, requirements gatherer

Teams: single team of designer-programmers

Seating: single big room, or adjacent offices


Getting started with Getting started with Crystal ClearCrystal Clear


Select the frequency of delivery, the length of the iteration and integration cycles.

Project: any length

Delivery: every two months

Delivery

Iteration: two weeksIteration

Iterations

Week

Integration: daily

Week

Integrations

Days Days

Integrations

EpisodesEpisode Episode Episode Episode Episodes

Integrations

Episodes


Must Do These !

1. Frequent Delivery : every month or two

2. Osmotic Communication : sit next to each other

3. Reflective Improvement : do reflection workshop monthly

Focus on the first 3 properties


Add these as you can !

4. Personal Safety : speak freely without fear of punishment

5. Focus : Know what is most critical, have time to work on it

6. Easy Access to Expert Users

7. Technical Environment with

- Frequent integration : hourly, daily, 3 / week

- Automated testing : unit tests, acceptance tests

- Configuration management : check-in, versioning

Simply start work, and stay in good-humored communication with with your teammates !


Hold a reflection workshop one day andeach month or iteration after that.

Keep these Try these

Problems

test lock-downquiet timedaily meetings

pair testingfines for interruptions

programmers help testers

too many interruptionsshipping buggy code


• Crystal is a genetic code for shaping your working conventions to your projec, always agile, focused on frequent delivery, close communication, and reflection.

• Crystal Clear is the lightest of the Crystal family, for 3-8 people working at the same location.

http://Alistair.Cockburn.us

Crystal is the lightest, least intrusive, success-oriented methodology.

the crystal family of methodologies for software development

Documents