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Copyright © 2002. The David Consulting Group, Inc. 1 UNDERSTANDING and EFFECTIVELY USING FUNCTIONAL MEASUREMENT Presented By The David Consulting Group.

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Presentation on theme: "Copyright © 2002. The David Consulting Group, Inc. 1 UNDERSTANDING and EFFECTIVELY USING FUNCTIONAL MEASUREMENT Presented By The David Consulting Group."— Presentation transcript:

1 Copyright © The David Consulting Group, Inc. 1 UNDERSTANDING and EFFECTIVELY USING FUNCTIONAL MEASUREMENT Presented By The David Consulting Group Stevens Institute of Technology

2 Copyright © The David Consulting Group, Inc. 2  Function Point Overview  Effective Use of Function Points  Establishing a Function Point Program PRESENTATION HIGHLIGHTS

3 Copyright © The David Consulting Group, Inc. 3 FUNCTION POINT OVERVIEW ä The Need for Sizing ä The Function Point Methodology ä A Sample Count

4 Copyright © The David Consulting Group, Inc. 4 CRITICAL SOFTWARE ISSUES ä Understanding the Customer’s Requirements ä Effectively Sizing the Requirements ä Accurately Estimating the Deliverable ä Managing a Successful Delivery PROCESS

5 Copyright © The David Consulting Group, Inc. 5 THE NEED FOR SIZING ä Quantitative (Objective) Measure ä Basis for Comparison ä Manage Expectations (Value) ä Satisfies SPI Requirements

6 Copyright © The David Consulting Group, Inc. 6 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)

7 Copyright © The David Consulting Group, Inc. 7 TYPES OF SIZING METRICS ä Lines of Code ä Artifacts ä Function Points Common Sizing Metrics

8 Copyright © The David Consulting Group, Inc. 8 MEASURING WITH LINES OF CODE äCan be counted consistently within organization äAvailable late in the life cycle äLines of code not always available äNo industry standard for counting lines of code äLimited ability to compare among various language groups äInternal use only, not meaningful to customer The Pros and Cons of Using SLOC

9 Copyright © The David Consulting Group, Inc. 9 SIZING FROM ARTIFACTS Determine size (and estimate) based on an evaluation of existing or planned artifacts Artifacts may include: ä Document size ä Number of screens, reports ä Programs/modules ä WBS

10 Copyright © The David Consulting Group, Inc. 10 FUNCTION POINTS 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.

11 Copyright © The David Consulting Group, Inc. 11 Function Point Analysis is a standardized method for measuring the functionality delivered to an end user. Function Point Counts have replaced Lines of Code counts as a sizing metric that can be used consistently and with a high degree of accuracy. FUNCTION POINTS IS AN EFFECTIVE SIZING METRIC

12 Copyright © The David Consulting Group, Inc. 12 ä A vehicle to estimate cost and resources required for software development, enhancement and maintenance ä A tool to quantify performance levels and to monitor progress made from software process improvement initiatives ä A tool to determine the benefit of an application to an organization by counting functions that specifically match requirements ä A tool to size or evaluate purchased application packages BENEFITS OF USING FUNCTION POINTS

13 Copyright © The David Consulting Group, Inc. 13 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)

14 Copyright © The David Consulting Group, Inc. 14 FUNCTION POINT ANALYSIS Definition ä Standard method for measuring software development from the customer’s point of view ä Quantifies functionality provided to the user based primarily on logical design Objectives ä Measure software development and maintenance independently of technology used for implementation ä Measure functionality that the user requests and receives

15 Copyright © The David Consulting Group, Inc. 15 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

16 Copyright © The David Consulting Group, Inc. 16 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

17 Copyright © The David Consulting Group, Inc. 17 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

18 Copyright © The David Consulting Group, Inc. 18 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

19 Copyright © The David Consulting Group, Inc. 19 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

20 Copyright © The David Consulting Group, Inc. 20 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

21 Copyright © The David Consulting Group, Inc. 21 BASIC COUNTING PROCESS ä Determine the type of function point count ä Identify the boundary for counting ä Count the data function types ä Count the transactional function types ä Determine the Function Point count

22 Copyright © The David Consulting Group, Inc. 22 Definition: Indicates the border between the project or application being measured and external applications or user domain Functionality: What Does a User See? + Data going into an application -- inputs + Data coming out of an application -- outputs, inquiries + Data, inside or outside an application -- logical files Data Inputs Outputs Application References/Feeds IDENTIFY THE BOUNDARY FOR COUNTING

23 Copyright © The David Consulting Group, Inc. 23 r An External Input (EI) processes data that comes from outside the application’s boundary. 1.0 Transaction ON-LINE ENTRY Multi-Screen UPDATE CUSTOMER INFORMATION CUSTOMER INFO FILE DEFINITION OF AN INPUT External Input

24 Copyright © The David Consulting Group, Inc. 24 DEFINITION OF AN OUTPUT r An External Output (EO) generates data that is sent outside the application boundary. END USER Summary SUMMARIZE CUSTOMER INFO 1.0 CUSTOMER INFO FILE External Output

25 Copyright © The David Consulting Group, Inc. 25 DEFINITION OF AN INQUIRY r An External Inquiry (EQ) is an output that results in data retrieval. The result contains no derived data. DISPLAY CUSTOMER INFO 1.0 END USER Selected Customer Info CUSTOMER INFO FILE External Inquiry

26 Copyright © The David Consulting Group, Inc. 26 DEFINITION OF A FILE r An Internal Logical File (ILF) is a user-identifiable group of logically related data that is maintained within the boundary of the application. UPDATE CUSTOMER INFO 1.0 CUSTOMER INFO FILE END USER Customer Info Updated Customer Info Internal Logical File

27 Copyright © The David Consulting Group, Inc. 27 DEFINITION OF A INTERFACE FILE r An External Interface File (EIF) is a user-identifiable group of data referenced by the application, but maintained within the boundary of another application. UPDATES ZIP CODE TABLE END USER 1.0 VALIDATE ZIP CODE & UPDATE CUSTOMER INFO CUSTOMER INFO FILE UPDATES VALID ZIP CODES External Interface File

28 Copyright © The David Consulting Group, Inc. 28 Components:LowAvg.High Total Internal Logical File (ILF) X 7 2 X 10 1X External Interface File (EIF) X 5 X 7X 10 0 External Input (EI) X 3X 4 2X 6 12 External Output (EO) 1 X 4X 5X 7 4 External Inquiry (EQ) X 3 2 X 4X 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

29 Copyright © The David Consulting Group, Inc. 29 AN EXERCISE IN COUNTING External Input External Inquiry External Output Internal Logical Files External Interface File Application

30 Copyright © The David Consulting Group, Inc. 30 USEFUL PROJECT/APPLICATION DOCUMENTATION 3 High Level System Diagrams 3 Logical Data/Process Models 3 Entity Relationship Models 3 Design Specifications 3 Requirements 3 Functional Specifications 3 Detailed Design 3 Layouts of Files and Databases 3 On-Line Screen Prints 3 User Manuals

31 Copyright © The David Consulting Group, Inc. 31 LOGICAL VIEW OF USER REQUIREMENT USER ADD, CHG INVOICES PAYMENTS VENDOR INVOICES ACCOUNTS PAYABLE USER PAYMENTS USER PAYMENT STATUS USER PAID INVOICES PURCHASE ORDER INFO PURCHASE ORDER SYSTEM

32 Copyright © The David Consulting Group, Inc. 32 Definition: Indicates the border between the project or application being measured and external applications or user domain APPLICATION BOUNDARY 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

33 Copyright © The David Consulting Group, Inc. 33 Components: LowAvg.High Total Internal Logical File (ILF) X 7 3 X 10 X External Interface File (EIF) X 5 1 X 7X 10 7 External Input (EI) X 3 3 X 4 X 6 12 External Output (EO) X 4 1 X 5X 7 5 External Inquiry (EQ) X 3 1 X 4X 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

34 Copyright © The David Consulting Group, Inc. 34 COMMON CRITICISMS WITH FUNCTION POINTS ä FP methodology terms are confusing ä Too long to learn, need an expert ä Need too much detailed data ä Does not reflect the complexity of the application ä “I did more work than I am getting credit for” ä Does not fit with new technologies ä Takes too much time ä We tried it before

35 Copyright © The David Consulting Group, Inc. 35 EFFECTIVE USE OF FUNCTION POINTS ä Requirements Management ä Estimating ä Benchmark Comparisons ä Managing Change

36 Copyright © The David Consulting Group, Inc. 36 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

37 Copyright © The David Consulting Group, Inc. 37 DEFINITION CAPABILITY ESTIMATE Schedule Effort Costs PROJECT SIZE X X RISK FACTORS PROJECT COMPLEXITY REQUIREMENT ESTIMATING MODEL SLOC Artifacts FUNCTION POINTS

38 Copyright © The David Consulting Group, Inc. 38 COMPLEXITY FACTORS Estimates are influenced by size and other factors such as complexity variables noted below: u Logical and mathematical algorithms u Code structure u Data relationships u Reuse u Memory u Security u Warranty

39 Copyright © The David Consulting Group, Inc. 39 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

40 Copyright © The David Consulting Group, Inc. 40 DEFINITION CAPABILITY ESTIMATE Schedule Effort Costs PROJECT SIZE X X RISK FACTORS PROJECT COMPLEXITY REQUIREMENT ESTIMATING MODEL PROFILE Data Relationships Code Structure Algorithmic Compl. Performance etc. Technology Skill Levels SQA Project Management etc.

41 Copyright © The David Consulting Group, Inc. 41 QUALITATIVE ASSESSMENT MEASURE ASSESS Size Effort Duration Defects Environment Definition Design Build Test Management Performance Productivity Capability Profiles Software Excellence

42 Copyright © The David Consulting Group, Inc. 42 D DEVELOPING A BASELINE OF DATA Product Deliverable Performance Indicators Risk Factors Time to Deliver - Duration - Number of days Management Definition Design Build Test Environment SIZE PRODUCTIVITY MEASURES PROFILES PROFICIENCIES INADEQUACIES A B C D A B C D : mnths 11 mnths 10 mnths 26 mnths 32 mnths

43 Copyright © The David Consulting Group, Inc. 43 Rate of Delivery Function Points per Person Month 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

44 Copyright © The David Consulting Group, Inc. 44 MONITORING IMPROVEMENTS Track Progress Rate of Delivery Function Points per Person Month Software Size Year 2 grouping of projects

45 Copyright © The David Consulting Group, Inc. 45 COMPARISONS TO INDUSTRY Industry Baseline Performance Rate of Delivery Function Points per Person Month Software Size

46 Copyright © The David Consulting Group, Inc. 46 ESTIMATING USING DELIVERY RATES PROJECT SIZE = DELIVERY RATE ESTIMATES – Effort PROJECT COMPLEXITY DEFINITION CAPABILITY Function Points Profiles

47 Copyright © The David Consulting Group, Inc. 47 ESTIMATING BEST PRACTICES The Software Engineering Institute (SEI) requirements for good estimating: u Corporate historical database u Structured processes for estimating product size and reuse u Mechanisms for extrapolating benchmark characteristics of past projects u Audit trails u Integrity in dealing with dictated costs and schedules u Data collection and feedback processes foster correct data interpretation

48 Copyright © The David Consulting Group, Inc. 48 ESTIMATING PROCESS SIZE REQUIREMENT Analyst ESTABLISH PROFILE SELECT MATCHING PROFILE GENERATE ESTIMATE WHAT IF ANALYSIS ACTUALS Counter Project Manager SoftwarePM / User Metrics DataBase Plan vs. Actual Report Profile Size Time The estimate is based on the best available information. A poor requirements document will result in a poor estimate Accurate estimating is a function of using historical data with an effective estimating process.

49 Copyright © The David Consulting Group, Inc. 49 CHANGE OF SCOPE MANAGEMENT InitialInterim EstimateEstimateEstimate Variance Function Points Effort (months) Schedule (months) Staffing Levels (FTE)33-0- Production Rate (FP/mo)

50 Copyright © The David Consulting Group, Inc. 50 Change of ScopeInputsOutputsInquiriesFilesInterfaces Total Add vendor function Graphical display Banking System Mandatory Changes Total 150 COMMUNICATING CHANGES IN SCOPE Function Point Change of Scope Summary

51 Copyright © The David Consulting Group, Inc. 51 AdditionalAdditional Additional FP EffortCost Schedule Change in ScopeCount(staff mo.) ($000)___(calend. mo.) Add Vendor Function Graphical Displays Banking System Mandatory Changes Total15010$ 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

52 Copyright © The David Consulting Group, Inc. 52 FUNCTION POINT PROGRAM ä Organizational Needs ä Benchmark Performance ä Measurement Selection ä Roadblocks

53 Copyright © The David Consulting Group, Inc. 53 A SUCCESSFUL SOFTWARE MEASUREMENT PROGRAM é FOCUS ON BUSINESS NEEDS é ESTABLISH PERFORMANCE LEVELS é PLAN WHAT TO MEASURE é DEFINE A MEASUREMENT PROCESS é BUILD A STRONG INFRASTRUCTURE é AUTOMATE

54 Copyright © The David Consulting Group, Inc. 54 BUSINESS NEEDS: SELECTION CRITERIA FOR MEASUREMENT 4 Align with business needs and the needs of the development organization 4 Select only a few metrics to implement initially 4 Create measures that are realistic and measurable 4 Use industry standard metrics to facilitate comparisons 4 Allow metrics to change and evolve as the organization matures

55 Copyright © The David Consulting Group, Inc. 55 FOCUS ON BUSINESS NEEDS ä Use of Goal-Question-Metric paradigm helps to identify the “right” measures Goal: Ensure that the correct goals are identified in support of the organization’s business drivers Question: Validated goals through a series of questions that ensure that the data collected will effectively measure the strategic goals Metric: The result is a metrics positioning statement which describes how the identified metrics support strategic business goals

56 Copyright © The David Consulting Group, Inc. 56 DETERMINE ORGANIZATION OBJECTIVES FOR EACH GOAL ä Example of using the Goal-Question-Metric paradigm Goal F Improve application development productivity Questions F Do we have a methodology for tracking productivity? F Do we want to collect data on new and/or enhancement projects? F Do we have time tracking capabilities? Metric F By tracking the hours throughout the life cycle of a project, we can use the productivity rate metric to determine if we are meeting our goal

57 Copyright © The David Consulting Group, Inc. 57 BASELINE CURRENT LEVELS OF PERFORMANCE ä What is baselining? A process involving the collection, analysis and reporting of performance data ä A performance baseline will: F Establish a "stake in the ground" from which improvement programs can be identified F Display qualitative data regarding the effectiveness of the techniques and methods currently being used F Permit the measurement of the impact of new tools, techniques and methods ä SSB Baseline F Levels of performance were established for productivity, work effort, duration and staffing levels

58 Copyright © The David Consulting Group, Inc. 58 BASELINE CURRENT LEVELS OF PERFORMANCE PERFORMANCE PRODUCTIVITY CAPABILITIES PERFORMANCE SOFTWARE PROCESS IMPROVEMENT TIME TO MARKET EFFORT DEFECTS MANAGEMENT SKILL LEVELS PROCESS TECHNOLOGYPRODUCTIVITY IMPROVEMENT INITIATIVES / BEST PRACTICES RISKS MEASURED BASELINE Sub Performance Best Practices Industry Averages Organization Baseline

59 Copyright © The David Consulting Group, Inc. 59 PLAN WHAT TO MEASURE ä Customer based metrics-- impact, value added ä Delivery metrics – responsiveness, quality ä Project metrics – effort, cost, duration ä Demand metrics -- backlog, type of work

60 Copyright © The David Consulting Group, Inc. 60 IMPACT MEASURES

61 Copyright © The David Consulting Group, Inc. 61 MEASUREMENT MATURITY ä Measures: ä Purpose: ä Business Metrics ä Customer Metrics ä Technology Metrics Project Focused Customer Focused Business Focused IT Efficiency Organizational Impact Business Impact Level 1 Level 2 Level 3 Effort/Cost Plan vs. Actual Production Problems Operational Customer Satisfaction Time to Market Size and Complexity Portfolio Management Defect Tracking Cost Reduction Increased Profitability Revenue Generation Process Improvement

62 Copyright © The David Consulting Group, Inc. 62 Recognizing And Overcoming Roadblocks, Challenges And Hurdles ä In order for your metrics program to not only survive, but flourish, adhere to the following: F Always have management and executive support F Choose your metrics personnel carefully, making sure that:  They will be enthusiastic supporters of the program  They have the determination to see the program succeed  They have the tenacity to keep pursuing individuals and project teams who are not cooperative F Properly set and manage expectations  Takes six months to begin collecting data, takes six more months to have data accuracy

63 Copyright © The David Consulting Group, Inc. 63 ã Be consistent and persistent F Make sure that everyone understands that this is not just “the flavor of the month” and that the metrics program is there to stay ã Educate! F Personnel includes executives, management, project leaders and the project team F Subjects include function points and metrics ã Share success F Communicate success stories to everyone in the organization Recognizing And Overcoming Roadblocks, Challenges And Hurdles

64 Copyright © The David Consulting Group, Inc. 64 ã Most Important… F Participants need to know what’s in it for them  Project team members need to be shown how the correct utilization of metrics can help them institute processes that will go a long way in creating projects that are “better, cheaper, faster”  This in turn can translate into project team recognition and rewards Recognizing And Overcoming Roadblocks, Challenges And Hurdles

65 Copyright © The David Consulting Group, Inc. 65 INFRASTRUCTURE ORGANIZATIONAL ISSUES Organizing for a Successful Function Point Program ä Centralization vs Decentralized Function Point counting is provided as a service vs. everyone (Project Managers) does the counting ä Policy and Procedures Policies define what gets counted (type, size) Procedures define how it gets counted (guidelines, lifecycle) Determine what gets counted ä Responsibility Who in the organization is involved in counting and what level of expertise do they require ä Certification Function Point Certification (CFPS) - IFPUG.org ä Tools Counter, DDB Software Function Point Workbench, Charismatek


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