Software Estimation
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Software Estimation

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Presentation on Software Estimation

Presentation on Software Estimation

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  • 1. Software Estimation Presented by – Dinesh Singh
  • 2. Agenda
    • Importance of Software Estimation
    • Type of Estimation
    • Estimation Tools/Techniques
    • Which Technique to use and when
    • Estimation Process
    • Estimation Tips
    • Explanation of Few Technique
    • Estimation Metrics
  • 3. Importance of Software Estimation
    • Budgeting & Decision Making
    • Forecast Profitability (IRR, NPV, Payback period, Benefit cost ratio , opportunity cost)
    • Reliable Resource Planning & Scheduling
    • Satisfied Customer
    • Under Estimation lead to loss, over estimation may loose business
    • Process Improvement
    • Fuzzy estimates can only lead to fuzzy project plans
  • 4. Type of Estimation
    • ( Size, Efforts , Schedule and cost)
    • Initiation (order of magnitude -25 to +75)
    • Budgetary (Planning -10 to +25)
    • Definitive ( Requirement -5 to +10)
    • Intermediate
    • Post construction
  • 5. Estimation Tools/Techniques
    • Top Down
      • Expert Judgment ( Experience & Historical data, Use Delphi method)
      • Analogous ( On similar projects, Top down)
      • Three point Analysis - (o+4m+p)/6
      • Reserve Analysis (Contingency, Management)
    • Bottom UP
      • Function Point Analysis
      • Use Case Point
      • Object Point Analysis
      • Program Complexity Method
      • COCOMO-Constructive Cost Model (Based on LOC)
  • 6. Which Technique to use and when
    • Function Point Analysis/Expert/ three point/reserve /Analogous
      • System is to be developed from scratch
      • Scope is available at broad level only
      • Person with high project management experience
    • Use Case Point / Object Point / PCM / Base sizing
      • Functionality is clear up to screen level
      • Enhancement of existing system
      • Scope is very clear
      • Person with good technical knowledge
  • 7. Estimation Process Collect Initial Requirement Estimate Size Estimate Efforts Produce Schedule Approve Estimate Develop Product Approved Actual Analyse Estimation Process Historical Project Data Resource Availability
  • 8. Tips
    • Create Details Work Break down structure till manageable level
    • Spend enough time to do proper Estimate
    • Involve Developer
    • Use more than one people and technique to estimate separately ( for large projects)
    • Use at least one estimation tool
    • Mine historical information to tune your estimation capability
    • Mention Dependencies and assumptions
  • 9. Function Point Analysis (FPA)
    • FPA
      • ILF ( Logical Entity resides on internal system)
        • e.g Customer Details
      • EIF ( External Entity referred by system)
      • EI ( User interaction screen , it may have ILF)
      • EQ ( Queries , does not update ILF or EIF)
      • EO (Across Application eg XML, can update ILF &EIF)
        • RET ( Normalization of the ILF & EIF)
        • DET ( User recognized data element type)
        • FTR ( Files used in transitions)
  • 10. Function Point Analysis (FPA)
    • ILF Function point
    • EIF Function point
    15 15 10 6 + RETs 15 10 7 2 - 5 RETs 10 7 7 1 RET 51+ DETs 20 - 50 DETs 1-19 DETs   10 10 7 6 + RETs 10 7 5 2 - 5 RETs 7 5 5 1 RET 51+ DETs 20 - 50 DETs 1-19 DETs  
  • 11. Function Point Analysis (FPA) EI Function point 6 6 4 3 + FTRs 6 4 3 2 FTRs 4 3 3 1 FTR 16 + DETs 5 -15 DETs 1- 4 DETs  
  • 12. Function Point Analysis (FPA) EO Function point 7 7 5 4 + FTRs 7 5 4 2 - 3 FTRs 5 4 4 1 FTR 20+ DETs 6- 19 DETs 1-5 DETs  
  • 13. Function Point Analysis (FPA) EQ Function point 6 6 4 4 + FTRs 6 4 3 2 - 3 FTRs 4 3 3 1 FTR 20+ DETs 6-19 DETs 1-5 DETs  
  • 14. Function Point Analysis (FPA)
    • Function point calculation
      • UFPC = Total of all function points
      • Degree of Influence on 14 points (Response time, transaction rate, ..)
      • VAF = 0.65 + (TDI *0.01)
      • Function point = UFPC * VAF
    • Efforts Estimate
      • 3 GL - 0.5 to 1 FP/day
      • 4 GL - 1 to 1.5 FP/day
      • 5 GL - 2 to 5 FP/day
  • 15.
    • FPA Template
    • OPE Template
    Exercise & Demo
  • 16. Three Magic formulae
    • Three Magic formulae
      • Project Duration = 2.5 * (Cube Root of Work Months)
      • Optimum Staffing Size = Square Root of Work Months
      • Minimum Duration = 0.75 * (Cube Root of Work Months)
  • 17. Estimation Metrics
    • Effort Slippage- ( Actual – Planned)*100/Planned
    • % Efforts used - Actual*100/Planned or budgeted
    • % Rework efforts- Rework*100 / Total
    • %Review & testing – Review & testing *100/ Total
  • 18. Q & A
  • 19. Thanks