ESD web seminar1 ESD Web Seminar February 23, 2007 Ricardo Valerdi, Ph.D. Unification of systems and software engineering cost models

ESD web seminar2 MIT Lean Aerospace Initiative USC CSSE Corporate Affiliate Program Lockheed Martin, BAE Systems, Northrop Grumman, SAIC, Raytheon, General Dynamics, L-3 Communications, Boeing INCOSE –Measurement Working Group –Corporate Advisory Board Practical Software & Systems Measurement (US Army) US Air Force Space & Missile Systems Center Cost Modeling Development Support

ESD web seminar3 Cost estimation 101 COCOMO & COSYSMO Activities & Phases Integration issues Next steps Roadmap

ESD web seminar4 My Purpose in Life To help people reason about their economic decisions related to software and systems engineering

ESD web seminar5 Cost Estimation Approaches 1.Parametric cost modeling –historical data 2.Expert judgment –Grey beards 3.Analogy –Compare with completed projects 4.Parkinson's Law –determined by available resources rather than by objective assessment 5.Pricing to win –whatever the customer has available 6.Top- down estimation –decompose logical function 7.Bottom- up estimation –Roll up

ESD web seminar6 Users for each model Acquirers, SW developers, estimators, systems engineers, managers, executives, or accountants who are interested in: –Software development (COCOMO II) –Commercial off the shelf software (COCOTS) –Systems engineering (COSYSMO) –Software quality (COQUALMO) –Software rapid application development (COPSEMO, CORADMO) –Software system of systems integration (COSOSIMO) –ROI/Investment analysis (iDave, COPLIMO)

ESD web seminar7 COCOMO IICOSYSMO EstimatesSoftware developmentSystems engineering Estimates size viaThousands of Software Lines of Code (KSLOC), Function Points, or Application Points Requirements, Interfaces, Algorithms, and Operational Scenarios Life cycle phasesMBASE/RUP Phases: (1) Inception, (2) elaboration, (3) construction, and (4) transition ISO/IEC Phases: (1) Conceptualize, (2) Develop, (3) Operation, Test, and Evaluation, (4) Transition to Operation, (5) Operate Maintain or Enhance, and (6) Replace or dismantle. Form of the model1 size factor, 5 scale factors, and 18 effort multipliers 4 size factors, 1 scale factor, 14 effort multiplier Represents diseconomy of scale through Five scale factorsOne exponential system factor

ESD web seminar8 COCOMO II COCOMO is the most widely used, thoroughly documented and calibrated software cost model COCOMO - the “COnstructive COst MOdel” –COCOMO II is the update to COCOMO 1981 –ongoing research with annual calibrations made available Originally developed by Dr. Barry Boehm and published in 1981 book Software Engineering Economics COCOMO II described in Software Cost Estimation with COCOMO II (Prentice Hall 2000)

ESD web seminar9 COCOMO II Phases & Modes Rational Unified Process (RUP) Inception Elaboration Construction Transition Modes Early design Post-architecture

ESD web seminar10 COCOMO Parametric Cost Estimating Relationship Where: A = constant derived from historical project data Size = software size measured in SLOC, FPs, or APs SF = scale factor EM = effort multiplier

ESD web seminar11 Software Sizing Alternative #1: Lines of Code –High Order Language LOC –Source LOC –Delivered SLOC Not a uniform metric Productivity across languages (backfire ratios) Alternative #2: Function-based metrics –Function points –Application points

ESD web seminar12 Scale Factors

ESD web seminar13 Effort Multipliers Product attributes –Required software reliability (RELY) –Database size (DATA) –Documentation match to life-cycle needs (DOCU) –Product complexity (CPLX) –Required Reusability (RUSE)

ESD web seminar14 Effort Multipliers (cont.) Platform attributes –Execution time constraint (TIME) –Main storage constraint (STOR) –Platform volatility (PVOL) Personnel attributes –Analyst capabilities (ACAP) –Applications experience (AEXP) –Programmer capabilities (PCAP) –Platform experience (PEXP) –Programming language experience (LEXP) –Personnel Continuity (PCON)

ESD web seminar15 Effort Multipliers (cont.) Project attributes – Use of software tools (TOOL) – Multisite Development (SITE) – Required Development Schedule (SCED)

ESD web seminar16 COCOMO Size Drivers Effort Multipliers Effort Calibration SLOC; or Function Points; or Application Points - Product attributes - Platform attributes - Personnel attributes - Project attributes COCOMO Operational Concept Schedule Scale Factors

ESD web seminar17 Historical Overview of COCOMO Suite of Models COQUALMO 1998 COCOMO COPROMO 1998 COSoSIMO 2004 Legend: Model has been calibrated with historical project data and expert (Delphi) data Model is derived from COCOMO II Model has been calibrated with expert (Delphi) data COCOTS 2000 COSYSMO 2002 CORADMO 1999 iDAVE 2003 COPLIMO 2003 COPSEMO 1998 COCOMO II 2000 DBA COCOMO 2004 COINCOMO 2004 Security Extension 2004 Costing Secure System 2004 Software Cost Models Software Extensions Other Independent Estimation Models Dates indicate the time that the first paper was published for the model

ESD web seminar18 COSYSMO Scope Addresses first four phases of the system engineering lifecycle (per ISO/IEC 15288) Considers standard Systems Engineering Work Breakdown Structure tasks (per EIA/ANSI 632) Conceptualize Develop Oper Test & Eval Transition to Operation Operate, Maintain, or Enhance Replace or Dismantle

ESD web seminar19 COSYSMO Size Drivers Effort Multipliers Effort Calibration # Requirements # Interfaces # Scenarios # Algorithms + 3 Volatility Factors - Application factors -8 factors - Team factors -6 factors WBS guided by EIA/ANSI 632

ESD web seminar20 Where: PM NS = effort in Person Months (Nominal Schedule) A = calibration constant derived from historical project data k = {REQ, IF, ALG, SCN} w x = weight for “easy”, “nominal”, or “difficult” size driver = quantity of “k” size driver E = represents diseconomy of scale EM = effort multiplier for the j th cost driver. The geometric product results in an overall effort adjustment factor to the nominal effort. Model Form

ESD web seminar21 4 Size Drivers 1. Number of System Requirements 2. Number of System Interfaces 3. Number of System Specific Algorithms 4. Number of Operational Scenarios Weighted by complexity, volatility, and degree of reuse

ESD web seminar22 14 Cost Drivers 1. Requirements understanding 2. Architecture understanding 3. Level of service requirements 4. Migration complexity 5. Technology Risk 6. Documentation Match to Life Cycle Needs 7. # and Diversity of Installations/Platforms 8. # of Recursive Levels in the Design Application Factors (8)

ESD web seminar23 14 Cost Drivers (cont.) 1. Stakeholder team cohesion 2. Personnel/team capability 3. Personnel experience/continuity 4. Process capability 5. Multisite coordination 6. Tool support Team Factors (6)

ESD web seminar 5 Fundamental Processes for Engineering a System Source: EIA/ANSI 632 Processes for Engineering a System (1999)

ESD web seminar25 ISO/IEC Conceptualize Develop Transition to Operation Operate, Maintain, or Enhance Replace or Dismantle EIA/ANSI 632 Acquisition & Supply Technical Management System Design Product Realization Technical Evaluation Operational Test & Evaluation SE Effort Profiling

ESD web seminar26 Integration Issues For each individual model as well as the unified model: 1.Objectives & Strategies 2.Inputs/scope of work 3.Output/scope of estimate 4.Assumptions of each model 5.Stakeholders for each model 6.Counting Rules 7.Data sources for calibration

ESD web seminar27 COCOMO II/COSYSMO Overlap COCOMO II is designed to estimate the software effort associated with the analysis of software requirements and the design, implementation, and test of software. COSYSMO estimates the system engineering effort associated with the development of the software system concept, overall software system design, implementation and test. Key to understanding the overlap is deciding which activities are considered “system engineering” and which are considered “software engineering/development” and how each estimation model handles these activities. Phases –ISO vs. MBASE/RUP Activities –EIA 632 vs. MBASE/RUP

ESD web seminar28 The numbers in the cells represent the typical percentage of effort spent on each activity during a certain phase of the software development life cycle as defined by COCOMO II. Each column adds up to 100 percent.

ESD web seminar29 Other Models Model NameOwner/Developer Constructive Cost ModelUSC PRICE-HardwarePRICE Systems PRICE-SoftwarePRICE Systems Raytheon SE Resource Forecasting ToolRaytheon SEER-HardwareGalorath SEER-Software Engineering ModelGalorath Small Satellite Cost ModelThe Aerospace Corp. Unmanned Satellite Cost ModelLos Angeles Air Force Base Hardware domainSoftware domain

ESD web seminar30 Contact Ricardo Valerdi (617)