Software Cost Estimation With Cocomo II

by Boehm, Barry W.; Abts, Chris; Brown, A. Winsor; Chulani, Sunita; Clark, Bradford K.; Horowitz, Ellis; Madachy, Ray; Reifer, Donald J.; Steece, Bert

• ISBN13: 9780130266927
• ISBN10: 0130266922
• Edition: CD
• Format: Hardcover w/CD
• Copyright: 2001-01-01
• Publisher: Prentice Hall

Summary

Don't become a statistic-take control of your software projects and plan for success! Success in all types of organization depends increasingly on the development of customized software solutions, yet more than half of software projects now in the works will exceed both their schedules and their budgets by more than 50%. While some types of overruns remain unpredictable, most can be avoided by sound modeling. COCOMO II provides you with a thorough rework of the classic COCOMO model to address modern software processes and construction techniques along with representative examples of applying the models to key software decision situations. It was calibrated and validated using innovative statistical techniques to fit both expert judgment and 161 carefully collected project data points. The book also introduces emerging COCOMO II extensions for cost and schedule estimation of COTS integration and rapid development. You'll also: bull; Learn firsthand from knowledgeable authors-over 100 person-years of software cost estimation experience Make better software decisions by exploring their cost implications Use the cost and schedule estimates to better plan and control your projects and manage your risks Get started now with the software on the accompanying CD Keep up to date with the authors' Web site Software engineers, managers, and students will all find Software Cost Estimation with COCOMO II an invaluable guide to developing and managing successful software projects on time and under budget. About the CD-ROM The accompanying CD-ROM includes a current copy of COCOMO II, along with demonstration versions of three commercial COCOMO II packages and an extensive documentation suite. All examples from the book are provided live, so you can work them hands on, along with the reading.

Table of Contents

List of Figures	xv
List of Tables	xxi
Foreword	xxvii
Preface	xxix
Acknowledgments	xxxv
About the Authors	xxxvii
Introduction to COCOMO II	1	(11)
COCOMO II User Objectives	1	(2)
COCOMO II Model Objectives	3	(1)
COCOMO II Development and Evolution Strategies	4	(2)
Future Software Practices Marketplace Model	6	(2)
Intermediate Sectors	7	(1)
1999 Model Assessment	8	(1)
Resulting Family of COCOMO II Models	8	(4)
COCOMO II Models for the Software Marketplace Sectors	8	(2)
Tailoring COCOMO II Estimation Models to Process Strategies	10	(2)
Model Definition	12	(71)
Introduction	12	(2)
Overview	12	(1)
Nominal-Schedule Estimation Equations	13	(1)
Sizing	14	(15)
Counting Source Lines of Code (SLOC)	14	(1)
Counting Unadjusted Function Points (UFP)	15	(4)
Relating UFPs to SLOC	19	(1)
Aggregating New, Adapted, and Reused Code	19	(6)
Requirements Evolution and Volatility (REVL)	25	(1)
Automatically Translated Code	26	(1)
Sizing Software Maintenance	27	(2)
Effort Estimation	29	(28)
Scale Factors	30	(6)
Effort Multipliers	36	(19)
Multiple Module Effort Estimation	55	(2)
Schedule Estimation	57	(1)
Software Maintenance	58	(1)
Using COCOMO II for Software Decisions	59	(9)
Making Investment Decisions and Business-Case Analyses	60	(1)
Setting Project Budgets and Schedules	61	(1)
Performing Tradeoff Analyses	61	(1)
Cost Risk Management	62	(1)
Development vs. Reuse Decisions	62	(1)
Legacy Software Phaseout Decisions	63	(1)
Software Reuse and Product Line Decisions	64	(2)
Process Improvement Decisions	66	(2)
Decision Analysis Summary	68	(1)
COCOMO II Model Summary and Versions	68	(15)
Model Equations, Tables, and Driver-Rating Scales	68	(6)
COCOMO II Version Parameter Values	74	(1)
Logical Lines of Source Code Counting Rules	75	(1)
COCOMO Model comparisons	75	(8)
Application examples	83	(57)
Introduction	83	(1)
Transaction Processing System (TPS) Overview	83	(32)
Transaction Processing System (TPS) Description	84	(1)
Transaction Processing System (TPS) Software Functions	85	(1)
Transaction Processing System (TPS) Software Development Organization	86	(1)
Transaction Processing System (TPS) Software Development Estimate	87	(16)
Bounding Risk	103	(4)
Conducting Trade Studies	107	(6)
Assessing Life-Cycle Costs	113	(2)
Airborne Radar System (ARS) Overview	115	(25)
ARS Description	116	(1)
Prototype Demonstration (Inception Phase)	116	(4)
Breadboard System (Elaboration Phase)	120	(4)
Full Development---Top-Level Estimate	124	(8)
Full Development---Detailed Component Estimate	132	(3)
Incremental Development Example	135	(5)
Calibration	140	(52)
Bayesian Calibration and COCOMO II Modeling Methodology	140	(4)
Bayesian Calibration	141	(1)
COCOMO II Modeling Methodology	142	(2)
Topics Addressed	144	(1)
COCOMO II Data Collection Approach	144	(7)
Obtaining Consistent Data	144	(1)
The Rosetta Stone	144	(7)
Model Building	151	(5)
Statistical Model-Building Process	151	(2)
Analysis of Observational Data	153	(3)
COCOMO II Calibration	156	(19)
COCOMO II.1997	156	(6)
COCOMO II.2000	162	(13)
Tailoring COCOMO II to a particular organization	175	(16)
Calibrating the model to existing project data	175	(6)
Consolidating or Eliminating Redundant Parameters	181	(10)
Adding Significant Cost Drivers That are not Explicit in the Model	191	(1)
Summary of COCOMO II Data	191	(1)
Conclusions	191	(1)
Emerging Extensions	192	(100)
Applications Composition: The Application Point Model	192	(5)
Object Point Data and Experiments	193	(1)
Application Point Estimation Procedure	193	(3)
Application Point Estimation Accuracy and Maturity	196	(1)
COPSEMO: Phase Schedule and Effort Estimation	197	(17)
Background	198	(5)
Model Overview	203	(3)
Model Implementation	206	(1)
Examples of Use	206	(1)
Dynamic COCOMO	207	(7)
CORADMO: Rapid Application Development Estimation	214	(23)
Background and Rationale	215	(1)
Relation to COCOMO II	216	(1)
Model Overview	217	(2)
Model Details	219	(11)
Scope And Life-cycle Addressed	230	(1)
Spreadsheet Model Implementation	231	(4)
Examples of Use	235	(1)
Conclusions	236	(1)
Future Work	236	(1)
COCOTS: COTS Integration Estimation	237	(17)
Background and Rationale	237	(2)
Relation to COCOMO II	239	(1)
Model Overview	240	(1)
Scope and Life Cycle Presently Addressed	241	(1)
Cost Sources	242	(1)
The Four Submodels	243	(1)
Assessment	243	(4)
Tailoring	247	(2)
Glue Code	249	(2)
System Volatility	251	(2)
Total COTS Integration Effort	253	(1)
Conclusion	253	(1)
COQUALMO: Quality Estimation	254	(14)
Introduction	254	(1)
Background Model	254	(1)
The Software Defect Introduction (DI) Model	255	(6)
The Software Defect Removel Model	261	(6)
COQUALMO Integrated with COCOMO II	267	(1)
Conclusions and Ongoing Research	267	(1)
COPROMO: Productivity Estimation	268	(16)
Background and Rationale	268	(1)
Relation to COCOMO II	269	(1)
Model Overview	270	(1)
Scope and Life Cycle Presently Addressed	270	(1)
Model Details	271	(4)
Spreadsheet Model Overview	275	(1)
Example of Use	275	(7)
COPROMO 0.3 Documentation	282	(1)
Conclusions and Future Work	283	(1)
Expert COCOMO: Risk Assessment	284	(8)
Introduction and Background	284	(1)
Risk Description	285	(1)
Risk Taxonomy and Rule Base	286	(1)
Risk Quantification	287	(1)
Input Anomalies	288	(1)
Implementation	288	(3)
Current Status and Further References	291	(1)
Future Trends	292	(9)
Trends in Software Productivity and Estimating Accuracy	292	(1)
Effects of Increasing Domain Understanding	293	(1)
Effects of Innovation and Change	294	(1)
Coping with Change: COCOMO II	295	(1)
Coping with Change: COCOMO II and Your Organization	296	(5)
Coping with Change During Project Definition	297	(1)
Coping with Change During Project Execution	297	(1)
Coping with Required COCOMO II Model Changes	297	(2)
Proactive Organizational Change Management	299	(2)
Appendix A COCOMO II: Assumptions and Phase/Activity Distributions	301	(27)
A.1 Introduction	301	(1)
A.2 Waterfall and MBASE/RUP Phase Definitions	302	(5)
A.2.1 Waterfall Model Phases and Milestones	302	(2)
A.2.2 MBASE and Rational Unified Process (RUP) Phases and Milestones	304	(3)
A.3 Phase Distribution of Effort and Schedule	307	(5)
A.3.1 Variations in Effort and Schedule Distributions	308	(2)
A.3.2 Distribution of Effort Across Life Cycle Phases	310	(1)
A.3.3 Distribution of Schedule Across Life Cycle Phases	311	(1)
A.4 Waterfall and MBASE/RUP Activity Definitions	312	(7)
A.4.1 Waterfall Model Activity Categories	312	(1)
A.4.2 Waterfall Model Work Breakdown Structure	312	(2)
A.4.3 MBASE/RUP Model Activity Categories	314	(5)
A.5 Distribution of Effort Across Activities	319	(7)
A.5.1 Waterfall Model Activity Distribution	319	(3)
A.5.2 MBASE/RUP Model Activity Distribution Values	322	(4)
A.6 Definitions and Assumptions	326	(2)
Appendix B COCOMO II: Estimating for Incremental Development	328	(9)
B.1 Introduction	328	(1)
B.2 Incremental Development Model	329	(2)
B.3 Inputs and Outputs	331	(1)
B.4 Estimation Steps	332	(4)
B.5 Incremental Development Considerations	336	(1)
Appendix C COCOMO Suite: Data Collection Forms and Guidelines	337	(51)
C.1 Introduction	337	(1)
C.2 Procedure for Projects	338	(2)
C.3 Guidelines for Data Collection	340	(2)
C.3.1 New Projects	340	(1)
C.3.2 Completed Projects	341	(1)
C.3.3 Maintenance Projects	342	(1)
C.4 Data Conditioning	342	(46)
C.4.1 Sources of Data Contamination	343	(1)
C.4.2 Data Conditioning Guidelines	344	(44)
Appendix D USC-CSE Affiliate Programs	388	(3)
D.1 Introduction	388	(1)
D.2 Primary Benefits	389	(1)
D.3 Additional Benefits	389	(1)
D.4 Levels of Affiliation	389	(1)
D.5 Current Affiliates	390	(1)
Appendix E USC COCOMO II.2000 Software Reference Manual	391	(81)
1.1 What is COCOMO?	391	(8)
1.1.1 Effort Estimation Equation	392	(1)
1.1.2 Schedule Estimation Equation	393	(1)
1.1.3 Scale Factors	393	(1)
1.1.4 Sizing Methods	394	(2)
1.1.5 FP: Counting with Unadjusted Function Points	396	(1)
1.1.6 AAF: Adaptation Adjustment Factors	397	(1)
1.1.7 Effort Multipliers	397	(2)
1.2 Navigating COCOMO	399	(7)
1.3 Begin Using COCOMO	406	(1)
1.4 Obtaining COCOMO	407	(1)
2.1 New	408	(1)
2.5 Load Project	409	(1)
2.3 Save Project	410	(1)
2.4 Save As Project	411	(1)
2.5 Load Model	412	(1)
2.6 Save Model	413	(1)
2.7 Save As Model	414	(1)
2.8 Make Report	415	(1)
2.9 Export	416	(5)
2.10 Save Screens	421	(1)
2.11 Print Screen	421	(2)
2.11 Print Preview	423	(1)
2.12 Print Setup	424	(1)
2.13 Exit	424	(1)
3.1 Add Module	425	(1)
3.2 Clear All Module	426	(1)
3.3 Snapshot	426	(1)
3.4 Undo	427	(1)
3.5 Cut	428	(1)
3.6 Copy	428	(1)
3.7 Paste	428	(1)
4.1 Post Architecture Model	429	(3)
4.1.1 Product	429	(1)
4.1.2 Platform	429	(1)
4.1.3 Personnel	430	(1)
4.1.4 Project	431	(1)
4.1.5 User Defined EAF	432	(1)
4.2 Early Design Model	432	(1)
4.3 Scale Factors	432	(1)
4.4 Equation	432	(2)
4.5 Person Month	434	(1)
4.5 Function Point	434	(2)
5.1 File Load	436	(1)
5.2 File Save	436	(1)
5.3 File Save As	436	(1)
5.4 Project	436	(2)
5.5 Compute	438	(2)
6.1 WaterFall Model---Project Phase Distribution	440	(6)
6.1.1 Waterfall Overall Project Phase	441	(1)
6.1.2 Waterfall Plans and Requirements Project Phase	442	(1)
6.1.3 Waterfall Programming Project Phase	443	(1)
6.1.4 Waterfall Product Design Project Phase	443	(2)
6.1.5 Waterfall Integration and Test Project Phase	445	(1)
6.2 Waterfall Model---Module Phase Distribution	446	(5)
6.2.1 Waterfall Overall Module Phase	447	(1)
6.2.2 Waterfall Plans and Requirements Module Phase	448	(1)
6.2.3 Waterfall Programming Module Phase	449	(1)
6.2.4 Waterfall Product Design Module Phase	449	(2)
6.2.5 Waterfall Integration and Test Module Phase	451	(1)
6.3 MBASE Model---Project Phase Distribution	451	(3)
6.3.1 MBASE Model Project Overall Phase	451	(1)
6.3.2 MBASE Model Project Inception	452	(1)
6.3.3 MBASE Model Project Elaboration	453	(1)
6.3.4 MBASE Model Project Construction	453	(1)
6.3.5 MBASE Model Project Transition	454	(1)
6.4 MBASE Model---Module Phase Distribution	454	(4)
6.4.1 MBASE Model Module Overall Phase	454	(1)
6.4.2 MBASE Model Module Inception Phase	455	(1)
6.4.3 MBASE Model Module Elaboration Phase	455	(1)
6.4.4 MBASE Model Module Construction Phase	456	(1)
6.4.5 MBASE Model Module Transition Phase	456	(2)
7.1 Project Maintenance	458	(2)
7.2 Module Maintenance	460	(12)
Appendix F Content of Accompanying CD-ROM	472	(5)
F.1 Introduction	472	(1)
F.2 Top-Level Screen	472	(1)
F.3 Install USC COCOMO II.2000	473	(1)
F.4 COCOMO II.2000 Manuals	473	(1)
F.5 The COCOMO Suite---Extensions and Companion Tools	474	(1)
F.5.1 COPSEMO Spreadsheet Models	474	(1)
F.5.2 CORADMO Spreadsheet Models	474	(1)
F.5.3 COPROMO Spreadsheet Models	474	(1)
F.5.4 Homepages of COCOMO II.2000 Suite and CodeCount™	474	(1)
F.6 Tutorials	475	(1)
F.7 Commercial COCOMO II.2000-Based Tools	475	(1)
F.8 Data Collection Forms	476	(1)
F.9 Affiliation	476	(1)
F.10 CD Top-Level Directory Highlights	476	(1)
Acronyms & Glossary	477	(8)
References	485	(8)
Index	493

Excerpts

Preface "We are becoming a software company" is an increasingly repeated phrase in organizations as diverse as finance, transportation, aerospace, electronics, and manufacturing firms. Competitive advantage increasingly depends on developing software for smart, tailorable products and services, and on the ability to develop and adapt these products and services more rapidly than competitors' adaptation times. These trends highlight the need for strong capabilities to accurately estimate software cost and schedules, and to support tradeoff, risk, sensitivity, and business case analyses for software decisions. Concurrently, a new generation of software processes and products is changing the way organizations develop software. These new approaches--evolutionary, risk-driven, and collaborative software processes; fourth-generation languages and application generators; commercial off-the-shelf (COTS) and reuse-driven software approaches; fast-track software development approaches; software process maturity initiatives--lead to significant benefits in terms of improved software quality and reduced software cost, risk, and cycle time. However, although some of the existing software cost models have initiatives addressing aspects of these issues, these new approaches have not to date been strongly matched by complementary new models for estimating software costs and schedules. This makes it difficult for organizations to conduct effective planning, analysis, and control of projects using the new approaches. These concerns have led the authors of this book to formulate a new version of the Constructive Cost Model (COCOMO) for software effort, cost and schedule estimation. The original COCOMO 81 Boehm 1981 and its specialized Ada COCOMO successor Boehm and Royce 1989 were reasonably well matched to the classes of software projects that they modeled: largely custom, built-to-specification software Miyazaki and Mori 1985; Goudy 1987. Although Ada COCOMO added a capability for estimating the costs and schedules for incremental software development, COCOMO 81 encountered increasing difficulty in estimating the costs of software created via spiral or evolutionary development models, or of software developed largely via commercial off-the-shelf (COTS) applications-composition capabilities. Software Estimation State of the Practice A number of commercial software estimation models continue to pass the market test for value added to users. And quite a few organizations do a good job of software project planning, estimating, and control. However, a very large number of organizations do not: in the 1995 Standish Group study, over 53% of the software projects were overrun by more than 50% in both budget and schedule Standish 1995. Some recent collections of software failure case studies provide more detail on the reasons for such overruns. Table P1 summarizes the results from six such projects. The first three are from Flowers 1996; the second three are from Glass 1998. Model Clashes and MBASE We have analyzed the projects in Table P1, and have found that many of their problems result from model clashes Boehm-Port 1999b. Model clashes involve incompatibilities among the primary models being used to define and manage the project. These include product models (requirements, architecture, design, etc.); process models (waterfall, spiral, maturity models, etc.); property models (cost, schedule, performance, etc.), and success models (business case, stakeholder win-win, IKIWISI: I'll know it when I see it, etc.). Table P1Software Overrun Case Studies First; Last Estimate Project Cost ($M) Schedule (Months) Status at Completion PROMS (Royalty collection) 12; 21+ 22; 46 Cancelled, Month 28

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