University of Southern California Center for Software Engineering CSE USC COSYSMO: Constructive Systems Engineering Cost Model Barry Boehm, USC CSE Annual Research Review February 6, 2001

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 2 Outline Background Scope Proposed Approach Strawman Model –Size & complexity –Cost & schedule drivers –Outputs Issues University of Southern California Center for Software Engineering CSE USC

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 3 Background Topic of breakout group at October 2000 COCOMO/SCM Forum Decided on incremental approach –Increment I: front-end costs of information systems engineering Coordinating with development of INCOSE-FAA systems engineering maturity data repository Also coordinating with Rational sizing metrics effort

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 4 Expand COCOMO II to information system engineering front end costs –Excluding aircraft, printer, etc. system engineering sensors a gray area –Excluding Transition effort for now –All of Inception and Elaboration effort –Construction: Requirements; Deployment; 50% of Design effort COSYSMO Increment I : Scope

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 5 Proposed System Engineering Scope: COCOMO II MBASE/RUP Phase and Activity Distribution

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 6 Develop strawman model –First iteration internally –Second iteration today –Discuss Issues (see below) –Initial assessment of relative cost/schedule driver influence Develop, experiment with revised model –Find appropriate Ph D student Proposed Approach

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 7 Strawman COSYSMO Sizing model determines nominal COCOMO II SysE effort and schedule –Function points/use cases for basic effort –Tool and document preparation separate (?) “source of effort” –Factor in volatility and reuse –Begin with linear effort scaling with size (?) Cost & Schedule drivers multiplicatively adjust nominal effort and schedule by phase, source of effort (?) –Application factors –Team factors

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 8 USC Strawman Sizing Model Function points, adjusted for complexity Use cases, adjusted for complexity –flows of events; complexity of interactions Rqts. Volatility factor similar to COCOMO II Reuse factor simpler than COCOMO II (TBD) Weighting of FP, use case quantities TBD Also use pairwise comparison approach for sizing –Compare with known systems Use COCOMO II CPLX factors for complexity (?) –Control, computability, device-dependent, data management, UI operations scales

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 9 Evolving Rational Sizing Model Objective: Obtain “software mass” for COCOMO engine USC “MVC” approach –“Model” -- number of classes of data –“View” -- number of use cases –“Control” -- distribution and algorithm complexity Size new application by MVC comparison to similar applications Overall, very similar to USC strawman sizing approach –Preparing to collaborate via Philippe Kruchten

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 10 Cost & Schedule Drivers: Application Factors Requirements understanding Architecture understanding Level of service rqts. criticality, difficulty External interface complexity Legacy transition complexity COTS assessment complexity (COCOTS- overlap?) Platform difficulty (PDIF - Early Design) Required business process reengineering

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 11 Cost & Schedule Drivers : Team Factors # of stakeholder communities –Average TEAM rating (COCOMO II scale factor) –Heterogeneity (domains, cultures) Personnel capability/continuity (PERS-Early Design) Personnel experience (PREX-Early Design) Process maturity (PMAT) Multisite coordination (SITE) Degree of system engineering ceremony Tool support (modified TOOL scale)

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 12 Strawman Model : Outputs Effort & schedule by phase –By activity ? –By source of effort (analysis, prototypes, tools, documents)? Risk assessment ?

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 13 Issues : Suggestions on Improving Scope Proposed Approach Model Form Model Elements Outputs Over/underlaps with COCOMO II, COCOTS, CORADMO Sources of data Staffing

University of Southern California Center for Software Engineering CSE USC 2/6/01 ©USC-CSE 14 COSYSMO: Factor Importance Rating Rate each factor H, M, or L depending on its relatively high, medium, or low influence on system engineering effort. Use an equal number of H’s, M’s, and L’s. Application Factors ______ Requirements understanding ______ Architecture understanding ______ Level of service rqts. criticality, difficulty ______ Legacy transition complexity ______ COTS assessment complexity ______ Platform difficulty ______ Required business process reengineering ______ TBD Team Factors ______ Number and diversity of stakeholder communities ______ Stakeholder team cohesion ______ Personnel capability/continuity ______ Personal experience ______ Process maturity ______ Multisite coordination ______ Degree of system engineering ceremony ______ Tool support ______ TBD