The use of FPA is on the rise again, at least in Requests for Proposal for new contracts. But what is a function point and what can you do with it or should better not be done. I gave my colleagues a brief introduction, that appeared to be interesting to a much wider audience, so I translated the original Dutch presentation to English.

1. FPA
Frank Vogelezang

2. FPA for Dummies 2
Agenda
 What is FPA
 How does FPA work
 What can you do with FPA
 What should better not be done with FPA
 Who owns FPA

3. FPA for Dummies 3
What is FPA
 FPA stands for Function
Point
Analysis
 What the software should be able to do (functionality) Function
expressed in a number Point
based on an objectively described method Analysis
 Something intangible like functionality becomes a physical number that can
be used for calculations

4. FPA for Dummies 4
How does function point analysis work
External Inquiry
External Input
External Output
Internal logical files
External input files

5. FPA for Dummies 5
How does function point analysis work
Counting function points
 Based on established criteria each element is
classified:
Simple
Complex
 Each classification has its own scores
Internal files 7 10 15
External interfaces 5 7 10
External input 3 4 6
External output 4 5 7
External inquiry 3 4 6
 A function point never travels alone

6. FPA for Dummies 6
What can you do with FPA
 Translate functionality into a physical number that can be used to calculate:
 Required amount of hours / cost
 Schedule time
 Basis for a fixed price (per unit) that is still variable
 The calculation depends on the technology used (Java, eBS, . . .)
 But it is not a linear calculation!
Twice the size in function points is not twice as much hours / cost / time

7. FPA for Dummies 7
What should better not be done with FPA
 Take into account activities that have no direct relation to the amount of
functionality of the software, like:
 Design / Specification
 Develop- and Testenvironments
 Data conversion
 Licences
 Combine all technologies in a single rate per function point
 Treat big and small projects the same in a single rate per function point
 Don’t take schedule compression into account in the rate per function point

8. FPA for Dummies 8
What should better not be done with FPA
In estimating packaged software the relation with the size expressed in function
points is unclear:
4993 Truck
4993 Cool Convertible 4993 Schaufelbagger
IWSM 2012 : Estimating Packaged Software Implementations - The first part of a framework

9. FPA for Dummies 9
What can you do with FPA – the hard part
 Hours / cost per function point depend on the number of function points
Hours / Cost
Function points
ISBSG : The cost of speed
Computable : Goed aanbesteden op basis van functiepunten

10. FPA for Dummies 10
What can you do with FPA – the really hard part
 Hours / cost do not only depend on size, but on schedule time as well
Effort
Minimal time
Realistic
Optimal effort
Schedule time

11. FPA for Dummies 11
Variations on the function point analysis theme
 NESMA has issued several guides:
 FPA for software enhancement (also in Portuguese)
 FPA applied to Data Warehousing
 Functional Sizing in a SOA environment (Dutch only)
 FPA in early phases
 They are not part of the ISO/IEC 24570 standard
 COSMIC
but that is a whole different story / standard
The additional guides can be downloaded free of charge from : www.nesma.nl Information on the COSMIC method is available on : www.cosmicon.com

12. FPA for Dummies 12
Who owns the function point method
 In the Netherlands the most commonly used method is the one from NESMA
NESMA = Netherlands Software Metrics users Association
This method is cerrtified as ISO/IEC 24570
 Worldwide the most commonly used FPA method is the one from IFPUG
IFPUG = International Fuction Point User Group
This method is cerrtified as ISO/IEC 20926

13. WatKostIT.blogspot.nl
ThePriceofIT.blogspot.com
@FrankVogelezang
FrankVogelezang frank.vogelezang@ordina.nl
www.linkedin.com/in/frankvogelezang
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