CMMI & PROCESS PATTERNS

Lecture - 04

Topics coveredCMMI-- Continuous model- Staged modelPROCESS PATTERNS-- Generic Process pattern elements

The Capability Maturity Model IntegrationSEI has developed a process meta-model on a set of

system & software engg. capabilities that should be present as organization reaches diff. levels of process capability and maturity.

“The quality of a product is largely determined by the quality of the process that is used to develop and maintain it.”

The CMMI frameworkThe CMMI framework is the current stage of

work on process assessment and improvement that started at the Software Engineering Institute in the 1980s.

The SEI’s mission is to promote software technology transfer particularly to US defence contractors.

It has had a profound influence on process improvementCapability Maturity Model introduced in the early 1990s.Revised maturity framework (CMMI) introduced in 2001.

Process capability assessmentIntended as a means to assess the extent to

which an organisation’s processes follow best practice.

My providing a means for assessment, it is possible to identify areas of weakness for process improvement.

There have been various process assessment and improvement models but the SEI work has been most influential.

InitialEssentially uncontrolled

RepeatableProduct management procedures defined and used

DefinedProcess management procedures and strategies defined

and usedManaged

Quality management strategies defined and usedOptimising

Process improvement strategies defined and used

The SEI capability maturity model

Problems with the CMMPractices associated with model levels

Companies could be using practices from different levels at the same time but if all practices from a lower level were not used, it was not possible to move beyond that level

Discrete rather than continuousDid not recognise distinctions between the top and the

bottom of levelsPractice-oriented

Concerned with how things were done (the practices) rather than the goals to be achieved.

The CMMI modelAn integrated capability model that includes

software and systems engineering capability assessment.

The model has two instantiationsStaged where the model is expressed in terms

of capability levels;Continuous where a capability rating is

computed.

CMMI model componentsProcess areas

24 process areas that are relevant to process capability and improvement are identified. These are organised into 4 groups.

GoalsGoals are descriptions of desirable organisational states.

Each process area has associated goals.Practices

Practices are ways of achieving a goal - however, they are advisory and other approaches to achieve the goal may be used.

CMMI process areas 1Process management Organisational process definition

Organisational process focusOrganisational trainingOrganisational process performanceOrganisational innovation and deployment

Project management Project planningProject monitoring and controlSupplier agreement managementIntegrated project managementRisk managementIntegrated teamingQuantitative project management

CMMI process areas 2Engineering Requirements management

Requirements developmentTechnical solutionProduct integrationVerificationValidation

Support Configuration managementProcess and product quality managementMeasurement and analysisDecision analysis and resolutionOrganisational environment for integrationCausal analysis and resolution

CMMI goalsGoal Process area

Corrective actions are managed toclosure when the projectÕs performanceor results deviate significantly from theplan.

Specific goal in ProjectMonitoring and Control

Actual performance and progress of theproject is monitored against the projectplan.

Specific goal in projectmonitoring and control

The requirements are analysed andvalidated and a definition of the requiredfunctionality is developed.

Specific goal inrequirementsdevelopment.

Root causes of defects and otherproblems are systematically determined.

Specific goal in causalanalysis and resolution.

The process is institutionalised as adefined process.

Generic goal

CMMI practicesPractice Associated goal

Analyse derived requirements to ensure that they arenecessary and sufficient

Validate requirements to ensure that the resultingproduct will perform as intended in the userÕsenvironment using multiple techniques asappropriate.

The requirements are analysed andvalidated and a definition of therequired functionality is developed.

Select the defects and other problems for analysis.

Perform causal analysis of selected defects and otherproblems and propose actions to address them.

Root causes of defects and otherproblems are systematically determined.

Establish and maintain an organisational policy forplanning and performing the requirementsdevelopment process.

Assign responsibility and authority for performingthe process, developing the work products andproviding the services of the requirementsdevelopment process.

The process is institutionalised as adefined process.

CMMI assessmentExamines the processes used in an organisation

and assesses their maturity in each process area.Based on a 6-point scale:

Not performed;Performed;Managed;Defined;Quantitatively managed;Optimizing.

Continuous CMMI meta model It describes a process in 2 dimensions as

shown in fig.capability level & process area

PP REQM MA CM PPQA0

1

2

3

4

5

Process area

capability level

Continuous model ..PROCESS AREAS :PP- project planningREQM- requirement managementMA- measurement & analysisCM- configuration managementPPQA- process & product quality assurance

Each process area is formally assessed against specific goals & practices and rated according to following capability levels

Capability LevelsLevel 0 - Incomplete

Process area is not performed or does not achieve all goals of level 1

Level 1 – Performedachieved all goals of level 1Work tasks conducted or performed

Level 2 – ManagedAll level 1 criteria satisfiedIn addition tasks & work products are monitored, controlled, reviewed & evaluated

Capability LevelsLevel 3 – Defined

All level 2 criteria satisfiedIn addition process is tailored from organizational standards of process to organizational process assets

Level 4 – Quantitatively managedAll level 3 criteria satisfiedIn addition process is improved & controlled using measurements & quantitative assessment

Level 5 – OptimizedAll capability 4 criteria have been achievedIn addition process area is adapted & optimized to meet changing customers need

CMMI staged ModelThe CMMI defines each process area in terms of

specific goals & specific practices required to achieve those goals

Specific Goals – establish the characteristics that must exist if the activities implied by a process area are to be effective

Specific practices- refine goal into a set of process related activities

Process PatternsSoftware process can be defined as a

collection of patterns

Templates or methods for describing important characteristics of software processes

Software teams can combine software patterns to construct processes that best meet the needs of specific projects

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Process Patterns..Process patterns define a set of activities,

actions, work tasks, work products and/or related behaviors

A template is used to define a patternTypical examples:

Customer communication (a process activity)Analysis (an action)Requirements gathering (a process task)Reviewing a work product (a process task)Design model (a work product)

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Generic Process pattern elementsMeaningful pattern name Intent (objective of pattern) Type

Task pattern (defines engineering action or work task) Stage pattern (defines framework activity for the process) Phase pattern (defines sequence or flow of framework activities

that occur within process)Initial context (describes conditions that must be

present prior to using pattern) Problem (describes the problem to be solved by

process pattern)Solution (describes how to implement pattern

correctly) Resulting context (describes conditions that result

when pattern has been implemented successfully) Related patterns (links to patterns directly related

to this one) Known uses/examples (instances in which pattern is

applicable)