1. Copyright © 2003. The David Consulting Group, Inc. 1 UNDERSTANDING and EFFECTIVELY USING FUNCTIONAL MEASUREMENT Presented By The David Consulting Group www.davidconsultinggroup.com NYC SPIN

2. Copyright © 2003. The David Consulting Group, Inc. 2  The Need for Sizing  Function Point Overview  Effective Use of Function Points PRESENTATION HIGHLIGHTS

3. Copyright © 2003. The David Consulting Group, Inc. 3 CRITICAL SOFTWARE ISSUES ä Understanding the Customer’s Requirements ä Effectively Sizing the Requirements ä Accurately Estimating the Deliverable ä Managing a Successful Delivery

4. Copyright © 2003. The David Consulting Group, Inc. 4 CHARACTERISTICS OF AN EFFECTIVE SIZING METRIC ä Meaningful to developer and user ä Defined (industry recognized) ä Consistent (methodology) ä Easy to learn and apply ä Accurate, statistically based ä Available when needed (early)

5. Copyright © 2003. The David Consulting Group, Inc. 5 äConsistent method äEasy to learn äAvailable early in the lifecycle äAcceptable level of accuracy äMeaningful internally and externally äResults are normalized across different environments Function Point Analysis is a standardized method for measuring the functionality delivered to an end user. FUNCTION POINTS IS AN EFFECTIVE SIZING METRIC

6. Copyright © 2003. The David Consulting Group, Inc. 6 FUNCTION POINT ANALYSIS Definition ä Standard method for measuring software development from the customer’s point of view Objectives ä Measure software development and maintenance independently of technology used for implementation ä Measure functionality that the user requests and receives

7. Copyright © 2003. The David Consulting Group, Inc. 7 FUNCTION POINT ANALYSIS - A LOGICAL VIEW Physical ä Lines of code or programs/modules ä Physical database or files ä Physical transactions (screens) Logical ä Functionality required ä Logical groups of user data ä Business processes

8. Copyright © 2003. The David Consulting Group, Inc. 8 THE FUNCTION POINT METHODOLOGY ä External Inputs ä External Outputs ä External Inquiries ä Internal Logical Files ä External Interface Files External Input External Inquiry External Output Internal Logical Files External Interface File Five key components are identified based on logical user view Application

9. Copyright © 2003. The David Consulting Group, Inc. 9 LOGICAL VIEW OF USER REQUIREMENT USER LIST OF MOLDS WORK CENTERS PARTS PLANT MOLDS PLANT INFORMATION CENTER USER BILL OF MATERIALS PARTS LISTING USER ORDER PARTS USER CHANGE BILL External Inquiries Internal Logical Files External Output External Inputs Interface VENDOR SUPPLY VENDOR INFORMATION

10. Copyright © 2003. The David Consulting Group, Inc. 10 Complexity Record Element Types Data Elements (# of unique data fields) or File Types Referenced Low Average High Low Average High Average High Components: Low Avg. High Total Internal Logical File (ILF) __ x 7 __ x 10 __ x 15 ___ External Interface File (EIF) __ x 5 __ x 7 __ x 10 ___ External Input (EI) __ x 3 __ x 4 __ x 6 ___ External Output (EO) __ x 4 __ x 5 __ x 7 ___ External Inquiry (EQ) __ x 3 __ x 4 __ x 6 ___ Total Unadjusted FPs Data Relationships Each identified component is assigned a Function Point size value based upon the make-up and complexity of the data 13 3 THE FUNCTION POINT METHODOLOGY

11. Copyright © 2003. The David Consulting Group, Inc. 11 General System Characteristics Data Communication On-Line Update Distributed Data Processing Complex Processing Performance Objectives Reusability Heavily Used Configuration Conversion & Install Ease Transaction Rate Operational Ease On-Line Data Entry Multiple-Site Use End-User Efficiency Facilitate Change The final calculation is based upon the Unadjusted FP count X VAF 14 General Systems Characteristics are evaluated and used to compute a Value Adjustment Factor (VAF) THE FUNCTION POINT METHODOLOGY

12. Copyright © 2003. The David Consulting Group, Inc. 12 SIZING THE REQUIREMENT USER ADD, CHG INVOICES PAYMENTS VENDOR INVOICES ACCOUNTS PAYABLE USER PAYMENTS USER PAYMENT STATUS USER PAID INVOICES PURCHASE ORDER INFO PURCHASE ORDER SYSTEM External Interface File External Inputs External Input External Inquiry External Output Internal Logical Files

13. Copyright © 2003. The David Consulting Group, Inc. 13 Components:LowAvg.High Total Internal Logical File (ILF) X 7 2 X 10 1X 15 35 External Interface File (EIF) X 5 X 7 1X 10 10 External Input (EI) 1 X 3X 4 2X 6 15 External Output (EO) 1 X 4X 5X 7 4 External Inquiry (EQ) X 3 1 X 4X 6 4 68 COMPONENTS ARE ASSESSED BASED UPON COMPLEXITY: Data Element Types (Fields or Attributes) File Types Referenced (ILFs or EIFs) Record Element Types (Data Sub-Groups) Function Point Count Complexity DETERMINE THE FUNCTION POINT COUNT

14. Copyright © 2003. The David Consulting Group, Inc. 14 WHEN TO COUNT FUNCTION POINTS CORRECTIVE MAINTENANCE PROPOSAL DESIGN TESTING DELIVERY REQUIREMENTS CONSTRUCTION SIZING Initial User Requirements Initial Technical Requirements Final Functional Requirements Feasibility Study SIZING Change Request Scope Adjustment SIZING

15. Copyright © 2003. The David Consulting Group, Inc. 15 Purpose To promote and encourage use of Function Points To develop consistent and accurate counting guidelines Benefits Networking with other counters IFPUG Counting Practices Manual Research projects Hotline Newsletter Certification Utilization Member companies include all industry sectors Over 1200 members in more than 30 countries INTERNATIONAL FUNCTION POINT USERS GROUP (IFPUG)

16. Copyright © 2003. The David Consulting Group, Inc. 16 EFFECTIVE USE OF FUNCTION POINTS ä Requirements Management ä Estimating ä Benchmark Comparisons ä Managing Change

17. Copyright © 2003. The David Consulting Group, Inc. 17 Functionality requested by the user may be organized into logical parts that match the five function point components MANAGING REQUIREMENTS USER ADD, CHG INVOICES PAYMENTS VENDOR INVOICES ACCOUNTS PAYABLE USER PAYMENTS USER PAYMENT STATUS USER PAID INVOICES PURCHASE ORDER INFO PURCHASE ORDER SYSTEM External Interface File External Inputs External Input External Inquiry External Output Internal Logical Files

18. Copyright © 2003. The David Consulting Group, Inc. 18 = 3200 square feet How long will it take to build? FUNCTION POINT SIZE – SO WHAT?

19. Copyright © 2003. The David Consulting Group, Inc. 19 DEFINITION CAPABILITY ESTIMATE Schedule Effort Costs PROJECT SIZE X X RISK FACTORS PROJECT COMPLEXITY REQUIREMENT ESTIMATING MODEL FUNCTION POINTS

20. Copyright © 2003. The David Consulting Group, Inc. 20 RISK FACTORS Estimates will also vary based upon a variety of risk factors: u Technology Applied such as tools, languages, reuse, platforms u Process/Methodology including tasks performed, reviews, testing, object oriented u Customer/User and Developer skills, knowledge, experience u Environment including locations, office space u System Type such as information systems; control systems, telecom, real-time, client server, scientific, knowledge-based, web u Industry such as automotive, banking, financial, insurance, retail, telecommunications

21. Copyright © 2003. The David Consulting Group, Inc. 21 Rate of Delivery Function Points per Person Month 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 024681012141618202224262830323436 Software Size ESTABLISHING A BASELINE Performance Productivity A representative selection of projects is measured Size is expressed in terms of functionality delivered to the user Rate of delivery is a measure of productivity Organizational Baseline

22. Copyright © 2003. The David Consulting Group, Inc. 22 COMPARISONS TO INDUSTRY Industry Baseline Performance Rate of Delivery Function Points per Person Month 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 024681012141618202224262830323436 Software Size

23. Copyright © 2003. The David Consulting Group, Inc. 23 PERFORMANCE PRODUCTIVITY CAPABILITIES PERFORMANCE PROCESS IMPROVEMENT TIME TO MARKET RESOURCES DEFECTS BUSINESS VALUE DELIVERABLES SKILL LEVELS PROCESS TECHNOLOGYCOSTS BARRIERS MEASURED PROFILE BASELINE PERFORMANCE

24. Copyright © 2003. The David Consulting Group, Inc. 24 CHANGE OF SCOPE MANAGEMENT InitialInterim EstimateEstimateEstimate Variance Function Points500650+150 Effort (months)3343+10 Schedule (months)1114+3 Staffing Levels (FTE)33-0- Production Rate (FP/mo)1515-0-

25. Copyright © 2003. The David Consulting Group, Inc. 25 Change of ScopeInputsOutputsInquiriesFilesInterfaces Total Add vendor function6-4 32 100 Graphical display--5 -- 20 Banking System311 1- 20 Mandatory Changes-2- -- 10 Total 150 COMMUNICATING CHANGES IN SCOPE Function Point Change of Scope Summary

26. Copyright © 2003. The David Consulting Group, Inc. 26 AdditionalAdditional Additional FP EffortCost Schedule Change in ScopeCount(staff mo.) ($000)___(calend. mo.) Add Vendor Function10071002.0 Graphical Displays201.220.4 Banking System201.220.4 Mandatory Changes10.610.2 Total15010$150 3.0 mos. COMMUNICATING IMPACT AND OPTIONS OPTIONS 1. Increase funding level and schedule 2. Reduce functionality, or do not accept change 3. Trade off quality and maintenance costs for schedule 4. Delay delivery of change

27. Copyright © 2003. The David Consulting Group, Inc. 27 GENERAL INFORMATION ä International Function Point Users Group www.ifpug.org ä International Software Benchmarking Standards Group www.isbsg.org.au ä Measuring The Software Process: A Practical Guide To Functional Measurements, Prentice Hall, 1996 ä Function Point Analysis; Measurement Practices for Successful Software Projects, Addison-Wesley, 2001