06/27/13 Santosh Dwivedi,PMP
Software Estimation &
Measurement
Santosh Dwivedi
06/27/13 Santosh Dwivedi,PMP
Agenda
 Why Estimate?
 What to Estimate?
 When to Estimate?
 How to Estimate?
06/27/13 Santosh Dwivedi,PMP
Why Don’t we estimate?
 I don’t have time
 Why estimate? When I have to anyway
deliver when...
06/27/13 Santosh Dwivedi,PMP
Why estimate?
 Because:
 Even if it is approximate we need to know the
size of the work
 U...
Why estimate?
 30% of project never complete
 100-200% cost overruns is not un-common
 Average project exceeds cost by ...
06/27/13 Santosh Dwivedi,PMP
Why Measure?
 Remember
 “If you don’t measure, you can’t manage”
 “If you don’t know where...
06/27/13 Santosh Dwivedi,PMP
What to Estimate?
 Estimation of the size of the system
 Estimation of effort
 Resource Re...
06/27/13 Santosh Dwivedi,PMP
When to Estimate?
 Estimation at RFP Stage Crude
 Estimation at beginning of
the project Be...
06/27/13 Santosh Dwivedi,PMP
How to Estimate? Cntd ..
Estimation Techniques:
The most popular and commonly used are:
 Lin...
06/27/13 Santosh Dwivedi,PMP
How to Estimate?
Estimation Basics
 Effort
 Size X Productivity
 Schedule
 Effort/Availab...
Estimating Schedule, Resource
from estimated effort
06/27/13 Santosh Dwivedi,PMP
Can we keep on compressing schedule by pu...
06/27/13 Santosh Dwivedi,PMP
Effort Overheads
(% of Base effort estimate)
Activity Small
project
Medium
project
Large
proj...
06/27/13 Santosh Dwivedi,PMP
Phase Wise Effort Distribution(%)
Phase Traditional
Development
Partial use of
CASE Tools
Com...
06/27/13 Santosh Dwivedi,PMP
How estimation data is used?
Size Effort Schedule Defect Density Compliance
Productivity, Cos...
Additional Sources of Information
06/27/13 Santosh Dwivedi,PMP
ISBSG
 http://www.isbsg.org
Charismatek (Function Point Wo...
06/27/13 Santosh Dwivedi,PMP
Thank You !!
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Software estimation and measurement

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A quick overview of software estimation and mesurement

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Software estimation and measurement

  1. 1. 06/27/13 Santosh Dwivedi,PMP Software Estimation & Measurement Santosh Dwivedi
  2. 2. 06/27/13 Santosh Dwivedi,PMP Agenda  Why Estimate?  What to Estimate?  When to Estimate?  How to Estimate?
  3. 3. 06/27/13 Santosh Dwivedi,PMP Why Don’t we estimate?  I don’t have time  Why estimate? When I have to anyway deliver when client wants  I know, what I am doing  It’s too tough and confusing  Not sure, if the productivity data is accurate  I just don’t have enough Information
  4. 4. 06/27/13 Santosh Dwivedi,PMP Why estimate?  Because:  Even if it is approximate we need to know the size of the work  Unless we start measuring, the productivity data will not evolve  Moreover, we need to measure our performance as how good or bad we are doing so that to drive improvements. Estimation is a pre-requisite for the measurement.
  5. 5. Why estimate?  30% of project never complete  100-200% cost overruns is not un-common  Average project exceeds cost by 90%; Schedule by 120%  15% of large project never deliver anything  Only 16.2% of projects are successful 06/27/13 Santosh Dwivedi,PMP
  6. 6. 06/27/13 Santosh Dwivedi,PMP Why Measure?  Remember  “If you don’t measure, you can’t manage”  “If you don’t know where you are standing, a map will not help”  “if you are not sure where you are going, any road will do” It’s no more tougher than the other activity we carryout. Give it a try
  7. 7. 06/27/13 Santosh Dwivedi,PMP What to Estimate?  Estimation of the size of the system  Estimation of effort  Resource Requirement  Estimation of schedule  The Timeline  Estimation of Cost  Pricing
  8. 8. 06/27/13 Santosh Dwivedi,PMP When to Estimate?  Estimation at RFP Stage Crude  Estimation at beginning of the project Better  Estimation at each phase of SDLC Even better  Measurement at End Perfect Estimation should be done at end of each phase of SDLC and the baseline should be revised, if required
  9. 9. 06/27/13 Santosh Dwivedi,PMP How to Estimate? Cntd .. Estimation Techniques: The most popular and commonly used are:  Line of Code (LOC)  Function Point Analysis (FPA) Work Breakdown Structure (WBS)  COCOMO Few others are:  Analogous  Parametric  Expert Judgment/Delphi Technique  Using Historical Data It is recommended to do estimation at least using two techniques to cross validate A detailed discussion on these estimation techniques is out of scope of this document and would need a separate document.
  10. 10. 06/27/13 Santosh Dwivedi,PMP How to Estimate? Estimation Basics  Effort  Size X Productivity  Schedule  Effort/Available Resource  Cost  Resource X Cost per resource + Overheads
  11. 11. Estimating Schedule, Resource from estimated effort 06/27/13 Santosh Dwivedi,PMP Can we keep on compressing schedule by putting more and more resources? “Nine women together can not produce a baby in a month” -Fred Brooks Common Rules:  Optimum Staffing (Persons) = SQRT(Effort) = (100)1/2 = 10.0  Optimal Project Duration (Months) = 2.5* (Effort)1/3 = 11.47  Min Duration (Months) = 0.75 *(Effort)1/3 = 3.47 These rules include standard project efforts: SCM, SQA, test, documentation
  12. 12. 06/27/13 Santosh Dwivedi,PMP Effort Overheads (% of Base effort estimate) Activity Small project Medium project Large project User documentation 10 10 10 Project Management 25 15 10 Quality Assurance 15 10 10 User training 10 07 05 Acceptance testing 10 05 05 Performance Tuning 05 08 10 Total (%age) 75 55 50
  13. 13. 06/27/13 Santosh Dwivedi,PMP Phase Wise Effort Distribution(%) Phase Traditional Development Partial use of CASE Tools Complete use of CASE Tools Requirement Analysis 15 25 40 High Level Design 10 15 25 Low Level Design 15 15 15 Code + Unit Test 40 35 10 Integration/ Module test 5 5 5 System Test 15 5 5
  14. 14. 06/27/13 Santosh Dwivedi,PMP How estimation data is used? Size Effort Schedule Defect Density Compliance Productivity, Cost Monitoring, End Timeliness, Process Performance Delivery Time, Customer Satisfaction, Cost Saving Project Leader/Project Manager Program Manager/Portfolio Manager Delivery Head
  15. 15. Additional Sources of Information 06/27/13 Santosh Dwivedi,PMP ISBSG  http://www.isbsg.org Charismatek (Function Point Workbench)  http://www.charismatek.com.au/_public1/html/fpw_o verview.htm Glossary of terms  http://www.sei.cmu.edu/str/indexes/glossary/ IFPUG site  http://www.ifpug.org Estimation  http://sunset.usc.edu/research  http://www1.jsc.nasa.gov/bu2/PCEHHTML/pceh.htm
  16. 16. 06/27/13 Santosh Dwivedi,PMP Thank You !!

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