Estimating the functional size

of an application portfolio with Oracle eBS applications

Frank VogelezangFrank Vogelezang

The challenge

• Determine the size of about 400applications in the portfolio in verydifferent development environments

• July through September3 months to deliver result

• Regular FP-count would cost up to7 person-Year of counting effort

The option of regular FP-Count

• Regular FP-count would require>23 full-time trained analysts>Detailed documentation available>Management pressure>Strong coordination attention>About 10 person-Year budget

• Regular FP-count was consideredto be too expensive and too risky

Functional size estimation

• Based on application characteristicsinstead of functional documentation

• Little FPA experience required but good application knowledge

• Less precise: 30% deviation

• Less expensive: 50% cheaper

The imprecision of size estimation

• An approximation of functional size

• Based on technical implementation

• Translating apples to oranges

Is it bad to be imprecise?

• Sizing technique should serve thepurpose of the project>Manage and control the portfolio>Serve as a basis for outsourcing contract

• Deviation of 30% is acceptable

• Spending extra money on precisionwould be a waste of resources

4993 Cool Convertible4993 Cool Convertible

A special challenge : Oracle eBS

A package containing already builtfunctionality that can be tailored to customer requirements

What functional size do I measure

• All the functionality that isavailable out-of-the box

• A subset of functionality thatis predefined for my business

• Only the functions that I havepicked to support my process

The chosen approach

• Size the functionality that is used

• Size estimation method>Query the different elements>Manually count some elements

• Verify the result with expectations>Review of queries and query results>Rules of thumb>Other size estimations (order of magnitude)

Query principles

1. Establish what Oracle eBS elementsshould be queried for each category

2. Establish what elements are used

3. Establish what elements are usedby the functionality that we areinterested in

Results for Oracle eBS

• 4 applications• 103,490 function points

• Size estimation>225 hours>Counting speed: 460 fp/hr

• Regular FP-Count: 2 person-Year

Results of the portfolio estimation

• 363 applications in 421 estimates• 316,720 function points• 67 staff involved• 5,300 hours spent:

>Training 200 hr>Size estimates 4,000 hr>Review 600 hr>Management 500 hr

• Counting speed: 69 fp/hr

Summary

• FP-Size can be estimated when there is no need for high precision counts

• Packaged applications can be estimated as well

• Size estimation is a cheaper and fast alternative for regular FP-Counts

Frank Vogelezang

frank.vogelezang@sogeti.nl

Twitter: @FrankVogelezang

metrieken.sogeti.nl