january 20, 2000 cse 7315 - sw project management / chapter 14 process improvement copyright ...

January 20, 2000 CSE 7315 - SW Project Management /

Chapter 14 – Process ImprovementCopyright © 1995-2000, Dennis J. Frailey,

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CHAPTER 14

PROCESS IMPROVEMENT

NOTICE: This material is copyrighted and may be copied or downloaded ONCE ONLY by students who are registered in this course at Southern Methodist University or National Technological University.



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Contents14.1 - General Issues14.2 - Continuous Process

Improvement14.3 - Process Reengineering



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14.1 - General Issues of Process Improvement

Textbook References

Topic Chapter• Defining the Process 13• Changing the Process 14• Improving the Process 17



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Process Improvement Begins with Process Management

• Know the process• Know the implications of changes -- on the outcome -- on the people -- on the reward system -- on the organizational infrastructure -- on the culture



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Change Requires Dealing with People

• Define what will happen• Document the actual processes• Teach people• Deal with their concerns• Buy-in is earned– Show by actions that you are serious– “Walk the Talk”– Avoid preaching– Let the people own the process and the change



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Quality ManagementGoal: Manage the software

engineering function to achieve high quality at low cost and cycle time

TimeCost Productive and CompetitiveQuality}



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The Quality Management Concept

HistoricalData Base- Metrics- Lessons- etc.

Process Models

Knowledgeand

Experience Project Goals



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Data Base• Know about your organization -- Metrics -- Lessons Learned -- etc.• Know about your industry and competitors -- What is best in class? -- Improvement rates -- etc.• Facts to help you manage

HistoricalData Base- Metrics- Lessons- etc.



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14.2 - ContinuousProcess Improvement

• Basic Idea: keep watching what you do, learning from mistakes, and fixing root causes of problems



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Models of Process Behavior• Theoretical models have scientific or

statistical bases for their predictions• Historical data of actual experience gives

valuable insight that theory may miss• Actual experience on current program is

the most relevant, if you can accurately measure it

All models give you a starting point and insight, but you must never fail to look at

the facts



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Using Models of Process Behavior

• Models can be used for training in what is expected

• Validation of experience against history and theory can help you understanding what is happening and why

• Assessment of differences between models and actuality can give insights into key attributes of your process

• Effective use of models will change management behavior, especially your own



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Example of Experience vs. History (we saw this example

earlier)• Suppose your experience suggests that for C++ doing your kind of software, you should be generating

-- 25 lines of code per day during the coding phase with

-- 3 errors per 1000 lines of code during module test

• Suppose your actual experience is -- 40 lines of code per day with -- 0.5 errors per 1000 lines of code during

module test



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Possible Conclusions1) We are doing much better than in the past -- Do you have a solid reason to explain this

difference? I.e., why are you better? o Is the process different? o Are the people a lot better? o Are the tools better?2) Our testing is no good (perhaps because it

is being rushed due to deadlines) o Are the tests being performed? o Is the coverage adequate? o etc.



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You Want to Achieve Optimal Performance

• Don’t over-measure or under-measure• Don’t over-test or under-test• Don’t over-inspect or under-inspect• etc.

Data + Models + Knowledge = Optimal Management



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Monitoring is Essential • Recall that our software cost and size

estimating models are based on -- historical data -- process models -- insight of model designer• These models are used to predict cost

and schedule• But the predictions are not exact • They identify the risks and they give

you a starting point for management



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UpdateProjections and Estimates

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10

ActualForecast



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If you monitor actuals against the predictions of models, then

you can• Revise the estimates based on new insight on parameters, assumptions, etc

• Calibrate the models based on your experience

original estimate

real data

recalibration

updated estimate



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Things you can Predict and Monitor

• Costs• Sizes• Quality• Reliability• Schedules• Staffing• etc.



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Predictions vs Process

Requirements Analysis

Design Code & Module

Test

SW Integ. & Test

Released Software

Predictions based on actual code

Predictions based on process and design

info

Actuals known



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In Order to Improve the Process, you need a Measure• Most organizations measure process in

terms of three quantities: -- productivity -- what is produced per unit

of cost -- cycle time -- time required to produce -- quality -- customer satisfaction level or

defects identified in released products• But few organizations have defined these

in a consistent way• So you need to start by defining these in a

way that fits your goals



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Example - Defect Density• We will look briefly at models and

how they might be used for managing defect levels



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Models of Defect Density

Goal: reduce defects to levels acceptable to the customer

Question: “how many defects are present in the system”?



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Initial ModelApproach: each step is modeled as

something that can inject new defects and eliminate defects

ProcessStep

I = Defects Input O = Defects Output

F = Defects Found and Fixed

C = Defects Created

O = I + C - F



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A More Detailed Defect Model of a Process Step

InjectDefects

escaping

defectsincomin

gdefects

undetected defects

detectdefects repair

defects

incorrect

repairs

defects remove

d

This model accounts for the mistakes we make when fixing

defects - I.e., the new defects we may

accidentally introduce



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Rayleigh Model of Defect Density (1)

Time

Total #of

Defectsin

System

05

101520253035

Start RqmtsReview

DesignReview

Code Review AcceptanceTest

2 t 2 -(t/c)2

f(t) = ----- * ---- * e t c ( ) (1) Kahn, S. H., IBM Systems

Journal, Vol. 30, #3 (1991)



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Exponential Model of Defect Density

Time

Total #of

Defectsin

System

01020304050607080

Release 3 months 6 months 9 months 1 year



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Strategies for Reducing Defects

• Problem - process variation is too wide, resulting in too many cases that are outside the acceptable limits

Unacceptable Quality



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Strategy 1: Be More Robust (widen the road)

Be robust enough to accommodate errors in incoming products

-- for software, this means each process step should tolerate incoming defects (e.g., prototypes, etc.)

-- it also means you should cultivate customers who tolerate lots of problems

Widen the Road



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Strategy 2: Produce fewer defects (narrow the car)

Reduce defects

-- for software, this means inspections, etc. to minimize defects in released software

Narrow the Car



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Combine Both of These to get Maximum Quality



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At each step of the process ...

• You have more information than before• So you can update your estimates• And make proper management decisions

You can also gain insight into process improvement if you tie actual data to models and try to understand what process problem caused you to be incorrect



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As a Rule ...• The general principles of

management tend to be independent of discipline

• But the measures tend to be discipline specific, especially those associated with product and process



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Another TendencyThe fundamental process problems tend

to be organic• That is, they are built into the

infrastructure and the culture• So you may need to make fundamental

and politically unpopular changes in order to make things better

• Sometimes only the need for survival is powerful enough to achieve this– “The competition is killing us because they

do it differently”



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Final Remarks• Start small -- appraisals should result in

small, doable improvements• Educate yourself - the more you know

about many things the better off you will be

• Look for process problems - working hard doing the wrong thing is wasteful, frustrating, and de-motivating

-- but many people consider this “business as usual” because they don’t know any better



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Process Reengineering• Basic Idea: from time to time, it is

necessary to reinvent the process• Motivation can come from:– intense competition– new technologies– new customers– new laws– other changes in the environment– realization that competition does it better– realization that you have not rethought the

issues in a long time and may be stagnating



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Changes Make Organizations and Processes Obsolete

You define your

organization to mirror or support a

given environment.

But environments change and changes can

make organizations less effective.



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Organizations Need Periodic Redesign or Reengineering

“We’ve always done it this way and it works just fine”

• Assess the environment• Rethink the processes• Reinstate the direct connections to– customers– suppliers– employees– etc.



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Example 1IBM Credit Approval Process• Before:

Credit Approval Must Go through Six Departments

Each Department takes 2-3 business daysSo Credit Approval takes 3 weeks

Meanwhile, the competition is approving credit in 1 week!

And we are losing sales because of this.



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Wrong SolutionIBM Credit Approval Process

Each department must reduce its cycle time to 1 day

Each department does this through incentives

It is accomplished by – Rejecting faulty input (even slightly faulty)– Producing output that is often defective

Result: Average Credit Approval takes 6 weeks!

Greatly increased rework!



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Reengineered SolutionIBM Credit Approval Process• One individual handles all six steps of each

transaction• The six former departments become

consultants, available to handle special cases but not involved in routine cases

Credit approvals reduced to 1 week!



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Example 2Graphic Artist Group

• Original Process:

Need

Graphic Artist Design

Group:Assignment

Dept

G1G2

G3G4

G5

Design

Graphic Artist Printing

Group:Assignment

Dept

P1P2

P3P4

P5

InspectionGood Products

Defective Products

More defects are generated on the second cycle!



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Reengineered Process forGraphic Artist Group

• Improved Process:

Need

AssignmentDept

G1G2

G3G4

G5

Design

P1P2

P3P4

P5

InspectionGood Products

Defective Products

By tying a graphic designer to a printer for the whole job, defects were repaired quickly and good products had greatly reduced cycle time.



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White SpaceA fundamental Problem of Of

Hierarchical Organizations

Too many handoffs between departments, where there is no responsibility at the point of need, only much higher in the organization



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Chapter Summary• Process Improvement requires knowing facts

(data) and using good models• Continuous process improvement will

remove the flaws of the process and improve results

• Reengineering is necessary to adjust to changes in the environment that require more substantial process changes

In the software business, change is relatively frequent and relatively significant

Although some principles do not change

january 20, 2000 cse 7315 - sw project management / chapter 14 process improvement copyright ...

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