1 PROJECT SIZING AND ESTIMATING - EFFECTIVELY USING FUNCTIONAL MEASUREMENT Southern California Software Process Improvement Network

Copyright © The David Consulting Group, Inc.2 Topics The User Perspective Program Start-up Characteristics of an Effective Sizing Metric Use of Function Points Project Estimation Quantitative & Qualitative Assessments Establishing and Using Baseline Data Modeling Improved Performance

Copyright © The David Consulting Group, Inc.3 “How do we indicate the value of sizing to our users/customers? When we say that a project represents 50 Function Points from the 'users perspective‘, what does this really mean to the user? or to the developer? How do we engage both parties in understanding size? The User Perspective Functional ‘value’ delivered to the user/customer Comparative analysis (size, cost per unit of work, defects) Functional description and accountability (user) Management of delivery expectations Credibility in project estimation

Copyright © The David Consulting Group, Inc.4 Program Start-up Planning How will the information be used (objectives)? Who is counting? What is being counted? History versus industry? Path of least resistance Easy to count (transaction based) Agreeable user Culture Internal versus external Pilot/rollout versus organization-wide Scope (what doesn’t get counted) Continually evaluating the program

Copyright © The David Consulting Group, Inc.5 Costs/Required Resources, Start-up and Ongoing Less than 1% of total budget (labor) Internal Training (several days) Mentoring Frequency/ skill level User group knowledge sharing External Economies of scale Awareness & orientation Internal resources required Positioned for Success Other measures to be utilized Process improvement activities monitored and measured

Copyright © The David Consulting Group, Inc.6 1 DESIGNTESTIMPLEMENT DEFINEBUILD SIZING When to Size 1)Initial sizing during or after Requirements Phase 2)Subsequent sizing after System Design or when Change occurs 3)Final sizing after Install SIZING 2 3

Copyright © The David Consulting Group, Inc.7 Meaningful to developer and user/customer Defined (industry recognized) Consistent (methodology) Easy to learn and apply Accurate, statistically based Available when needed (early) Addresses project level information needs Characteristics of an Effective Sizing Metric

Copyright © The David Consulting Group, Inc.8 Function Point Analysis is a standardized method for measuring the functionality delivered to an end user. Function Points - An Effective Sizing Metric Benefits: Quantitative (Objective) Measure Industry Data as Basis for Comparison Expectations (Perceived Customer Value) Managed Software Process Improvement Requirements Satisfied

Copyright © The David Consulting Group, Inc.9 A vehicle to estimate cost and resources required for software development, enhancements and/or maintenance A tool to quantify performance levels and to monitor progress made from software process improvement initiatives A tool to determine the benefit of an application to an organization by counting functions that specifically match requirements A tool to size or evaluate purchased application packages Benefits of Using Function Points

Copyright © The David Consulting Group, Inc.10 Approach to Function Points A function point count is performed to produce a functional size measure The size can be used to generate project estimates Estimates should be based upon delivery rates Analysis - plan versus actual comparisons How good is the information received during requirements? How good (accurate) is project estimating?

Copyright © The David Consulting Group, Inc.11 Review the available documentation Meet with SME to gain a thorough understanding of the functionality Apply the function point methodology, and compute a functional size Generate an estimate based on available delivery rates Function Point Counting Process

Copyright © The David Consulting Group, Inc.12 Inputs Outputs Inquiries Internal Logical Files External Interface Files InputInquiry Output Internal Logical Files External Interface File Five key components are identified based on logical user view Application The Function Point Methodology

Copyright © The David Consulting Group, Inc.13 USER LIST OF MOLDS WORK CENTERS PARTS PLANT MOLDS PLANT INFORMATION CENTER USER BILL OF MATERIALS PARTS LISTING USER ORDER PARTS USER CHANGE BILL Inquiries Internal Logical Files Output Inputs Interface VENDOR SUPPLY VENDOR INFORMATION Logical View of User Requirements

Copyright © The David Consulting Group, Inc.14 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

Copyright © The David Consulting Group, Inc.15 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 Optional General Systems Characteristics are evaluated and used to compute a Value Adjustment Factor (VAF) The Function Point Methodology

Copyright © The David Consulting Group, Inc.16 Function Point Calculation Enhancement FPs as they relate to existing master count: External Inputs (EI) (2) – Add/Change Account; change; high complexity; total unadjusted FPs = 2 x 6 = 12 External Input (EI) –Issue Material; change; high complexity; total unadjusted FPs = 1 x 6 = 6 External Input (EI) – Add Tax; change; low complexity; total unadjusted FPs = 1 x 3 = 3 Total Unadjusted FPs: 21 Value Adjusted Factor: 1.01 Total Adjusted FPs: 21

Copyright © The David Consulting Group, Inc.17 Example – Counting Accuracy Estimate: Resulting size =150 function points Matching profile, rate of delivery = 10 FP/EM Estimated effort = 15 effort months Actuals:Results Size175 fps +17% Effort19 effort months +27%

Copyright © The David Consulting Group, Inc.18 Example – Scope Accuracy Counting ActivityFP Resulting Requirements size =120 Resulting Design size = 144 Resulting Install size =174 Analysis: InputsOutputs Inquiries Interfaces FilesTotal

Copyright © The David Consulting Group, Inc.19 PROJECT SIZE X X RISK FACTORS PROJECT COMPLEXITY DEFINITION CAPABILITY ESTIMATE Schedule Effort Costs REQUIREMENT FUNCTION POINT ANALYSIS Project Estimation

Copyright © The David Consulting Group, Inc.20 Capability Analysis Collect project data Project metrics (e.g., effort, size, cost, duration, defects) Project characteristics Project attributes (e.g., skill levels, tools, process, etc.) Project complexity variables Analyze data Performance comparisons (identification of process strengths and weaknesses) Industry averages and best practices Performance modeling (identify high impact areas)

Copyright © The David Consulting Group, Inc.21 DCG Data Base CharacteristicsComplexity Variables Project Type Platform Data Base Method Language MetricsAttributes Size Management Cost Definition Effort Design Duration Build Defects Test Environment Logical Algorithms Code Structure Mathematical Algorithms Performance Data Relationships Memory Functional Size Security Reuse Warranty Process Skill Levels Quality Practices Measures

Copyright © The David Consulting Group, Inc.22 Quantitative & Qualitative Assessments MEASURES Research PROFILES PERFORMANCE LEVELS CHARACTERISTICS Software Size Level of Effort Time to Market Delivered Defects Cost Skill Levels Automation Process Management User Involvement Environment Analysis Results Correlate Performance Levels to Characteristics Substantiate Impact of Characteristics Identify Best Practices

Copyright © The David Consulting Group, Inc.23 PROJECT SIZE and COMPLEXITY RATE OF DELIVERY DEFINITION CAPABILITY ESTIMATE Schedule Effort Costs REQUIREMENT FUNCTION POINT SIZE Estimating Using Historical Delivery Rates FUNCTION POINTS Per EFFORT MONTH

Copyright © The David Consulting Group, Inc.24 Analysis of Results Analyze estimating accuracy Plan vs. actual comparisons Effectiveness of delivery rates Evaluate the system level documentation Change in scope (size) through the various stages Clarity of requirements and design documents Recommend improvements Improve the level of documentation for more accurate sizing Establish a more effective estimating practice

Copyright © The David Consulting Group, Inc.25 D Product Deliverable Performance Profiles Time to Deliver - Duration - Number of days Level of Effort Defects Size Platform Language SIZE PROJECT MEASURES PROFILES Rate of Delivery Time to Market Defect Density A B C D A B C D : mnths 35 effort mnths 10 defects Develop a Baseline of Data

Copyright © The David Consulting Group, Inc.26 Establish A Baseline Software Size Size is expressed in terms of functionality delivered to the user Rate of delivery is a measure of productivity Rate of Delivery Function Points per Person Month Performance Productivity A representative selection of projects is measured Organizational Baseline

Copyright © The David Consulting Group, Inc.27 Compare To Industry Benchmarks Industry baseline performance Rate of Delivery Function Points per Person Month Software Size

Copyright © The David Consulting Group, Inc.28 Function Points Per Person Month Web22 e-business Web12 Client Server15 Main Frame13 Vendor Packages 19 Data Warehouse11 Average of Recent Projects Across Different Platforms

Copyright © The David Consulting Group, Inc.29 Function Points Supported By One FTE Web 748 e-business Web464 Vendor Packages 760 Data Warehouse546 Client Server 642 Main Frame 943 AS Average of Support Provided for Corrective Maintenance by One FTE

Copyright © The David Consulting Group, Inc.30 Analyze Results COLLECT QUANTITATIVE DATA COLLECT QUALITATIVE DATA Process Methods Skills Tools Management Measured Performance Capability Profiles Baseline Performance Collection Analysis Results Action Opportunities For Improvement Best Practices Size Effort Duration Cost Quality

Copyright © The David Consulting Group, Inc.31 Develop parametric models that utilize historical data points for purposes of analyzing the impact of selected process improvements Provide a knowledge base for improved decision making Identify areas of high impact (e.g., productivity and quality Create an atmosphere of measuring performance Opportunity for comparison to industry best practices Model Performance

Copyright © The David Consulting Group, Inc.32 COLLECT QUANTITATIVE DATA Size Effort Duration Cost Quality Measured Performance Quantitative Assessment Perform functional sizing on all selected projects. Collect data on project level of effort, cost, duration and quality. Calculate productivity rates for each project, including functional size delivered per staff month, cost per functional size, time to market, and defects delivered. Results Quantitative Performance Evaluation

Copyright © The David Consulting Group, Inc.33 COLLECT QUALITATIVE DATA Process Methods Skills Tools Management Capability Profiles Results Qualitative Assessment Conduct Interviews with members of each project team. Collect Project Profile information. Develop Performance Profiles to display strengths and weaknesses among the selected projects. Qualitative Performance Evaluation

Copyright © The David Consulting Group, Inc.34 Process Improvements: Code Reviews and Inspections Requirements Management Defect Tracking Configuration Management Performance Improvements: Productivity ~ +131% Time to Market ~ -49% Defect Ratio ~ -75% SAMPLE DATA Modeled Improvements

Copyright © The David Consulting Group, Inc.35 Conclusions Project Management can be successful Requirements can be managed Projects can be sized Performance can be successfully estimated Process improvement can be modeled Measurement can be accomplished

Copyright © The David Consulting Group, Inc.36 Contact Information David Consulting Group web site: David Garmus

Copyright © The David Consulting Group, Inc.37 Contact Information International Function Point Users Group (IFPUG) Practical Software and Systems Measurement (PSM) Software Engineering Institute (SEI) Software Quality Engineering (SQE) Quality Assurance Institute (QAI)