1. Software Development Estimation
Dark Art or Science?
Stefan Kiryazov (Vereo, Wizefish)

2. инвестираме в бъдещето

3. wizefish.com
Софтуерни решения за успешен бизнес

4. Introduction Target audience Required background skills
Senior software developers
Technical leaders
Project managers
High level managers
Customers
Required background skills
Familiarity with the software development process

5. Causes for Uncertainty Presenting Estimates Estimation Process
Contents
Causes for Uncertainty
Presenting Estimates
Estimation Process
Corporate Portals, Enterprise Portals, Enterprise Portal Servers

6. Background Why is estimating important?
A foundation for efficient development
Estimate too high – Parkinson’s law
Estimate too low – inefficient planning
Is perfect estimating possible?
The software estimating story

7. Cost Budgeting

8. Causes for Uncertainty
Will the customer want Feature X?
Will the customer want the cheap or expensive version of Feature X?
If we go for the cheap, will he/she want the expensive one later after all?
How will Feature X be designed?
How long will it take to fix the bugs in Feature X?
How long will it take to integrate Feature X?

9. Causes for Uncertainty
Software development – a process of gradual refinement
The perfect estimate is doing the project work itself
The earlier, the less precise

10. Estimate Convergence Graph

11. “It is the mark of an instructed mind to rest satisfied with the degree of precision which the nature of the subject admits and not to seek exactness when only an approximation of the truth is possible …”
Nichomachean Ethics, Aristotle

12. The Schedule Graph

13. Optimistic Schedule Graph

14. Avoid overprecise estimates
Presenting Estimates
Presentation styles
Plus/minus
Conditions
Cases
Ranges
Avoid overprecise estimates
Accuracy vs precision
Use coarse periods

15. Estimation Process
Size estimation
Effort estimation
Schedule estimation

16. Compare with past projects
Size Estimation
What is size?
Function points
Lines of code
Custom measurement
Compare with past projects
Compare with documented data, not personal memory

17. Derived from size estimate No off-the-cuff estimates!
Effort Estimation
Derived from size estimate
No off-the-cuff estimates!
Even with conditions!
Estimate at high level of detail
Law of large numbers

18. Don’t omit common tasks Developer based estimates
Effort Estimation
Don’t omit common tasks
Developer based estimates
Sanity checking
Commitment-based estimates
Compare estimates

19. The Cost Graph

20. Compression increases cost!
Schedule Estimation
The nominal schedule
Schedule = 3 * Effort1/3
Schcedule – months, Effort - manmonths
Schedule compression
Compression Factor (CF) = Nominal / Compressed
Compression increases cost!
Compressed cost = Initial cost / CF

21. Questions ?
Provide some feedback, please!