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Estimation Challenges for 21st Century Software Systems

Software Track




Several future trends will present significant future challenges for the sizing and cost estimation of 21st century software systems. Prominent among these trends are:

1. Rapid change, emergent requirements, and evolutionary development. These trends will require more attention to cost uncertainty ranges, requirements volatility, and a new factor called the Incremental Development Productivity Decline (IDPD).

2. Net-centric systems of systems. This will require more attention to both requirements volatility and complexity of internal-component and external-component coupling.

3. Model-Driven and non-developmental item (NDI)-intensive systems. This will require more attention to sizing model-driven development, COTS-intensive systems, and use of cloud computing services.

4. Ultrahigh software system assurance. This will require extended rating scales and calibrated effort multipliers for ultrahigh assurance, and also methods of sizing additional security and safety functions.

5. Legacy maintenance and brownfield development. Legacy maintenance will require more nuanced cost drivers than annual change traffic. Brownfield will require better approaches to sizing and costing of legacy system re-engineering.

6. Agile and kanban development. These involve different estimation methods such as Planning Poker, and offer the opportunity to relax estimation accuracy by using timeboxing and meeting schedules by dropping low priority features where necessary, or by using kanban workflow management methods.

This paper summarizes each trend, elaborates on its challenges for software sizing and cost estimation, and offers starting points for addressing the challenges.


Barry Boehm
University of Southern California
Dr. Barry W. Boehm is the TRW Professor of Software Engineering and Director Emeritus, Center for Software Engineering, University of Southern California.

Barry Boehm received his B.A. degree from Harvard in 1957, and his M.S. and Ph.D. degrees from UCLA in 1961 and 1964, all in Mathematics. He also received an honorary Sc.D. in Computer Science from the U. of Massachusetts in 2000.

Between 1989 and 1992, he served within the U.S. Department of Defense (DoD) as Director of the DARPA Information Science and Technology Office, and as Director of the DDR&E Software and Computer Technology Office. He worked at TRW from 1973 to 1989, culminating as Chief Scientist of the Defense Systems Group, and at the Rand Corporation from 1959 to 1973, culminating as Head of the Information Sciences Department. He was a Programmer-Analyst at General Dynamics between 1955 and 1959.

His current research interests focus on value-based software engineering, including a method for integrating a software system’s process models, product models, property models, and success models called Model-Based (System) Architecting and Software Engineering (MBASE). His contributions to the field include the Constructive Cost Model (COCOMO”), the Spiral Model of the software process, the Theory W (win-win) approach to software management and requirements determination, the foundations for the areas of software risk management and software quality factor analysis, and two advanced software engineering environments: the TRW Software Productivity System and Quantum Leap Environment.

He has served on the boards of several scientific journals, including the IEEE Transactions on Software Engineering, IEEE Computer, IEEE Software, ACM Computing Reviews, Automated Software Engineering, Software Process, and Information and Software Technology. He has served as Chair of the AIAA Technical Committee on Computer Systems, Chair of the IEEE Technical Committee on Software Engineering, and as a member of the Governing Board of the IEEE Computer Society. He has also served as Chair of the Air Force Scientific Advisory Board’s Information Technology Panel, Chair of the NASA Research and Technology Advisory Committee for Guidance, Control, and Information Processing, and Chair of the Board of Visitors for the CMU Software Engineering Institute.

His honors and awards include Guest Lecturer of the USSR Academy of Sciences (1970), the AIAA Information Systems Award (1979), the J.D. Warnier Prize for Excellence in Information Sciences (1984), the ISPA Freiman Award for Parametric Analysis (1988), the NSIA Grace Murray Hopper Award (1989), the Office of the Secretary of Defense Award for Excellence (1992), the ASQC Lifetime Achievement Award (1994), the ACM Distinguished Research Award in Software Engineering (1997), and the IEEE Harlan D. Mills Award (2000). He is a Fellow of the primary professional societies in computing (ACM), aerospace (AIAA), electronics (IEEE), and systems engineering (INCOSE), and a member of the National Academy of Engineering.

Brad Clark
Dr. Brad Clark is Vice-President of Software Metrics Inc. – a Virginia based consulting company. He is also a Research Associate with the Center for Systems and Software Engineering at the University of Southern California. He works with the Center on issues concerning data collection, analysis, and modeling. Dr. Clark received his Ph.D. in Computer Science in 1997 from the University of Southern California. Brad is a former Navy A-6 Intruder pilot.

Raymond J. Madachy
Naval Postgraduate School
Dr. Raymond Madachy is an Associate Professor in the Systems Engineering Department at the Naval Postgraduate School. Previously he was a Research Assistant Professor in the Industrial and Systems Department at the University of Southern California and a Principal in the USC Center for Systems and Software Engineering. At USC he also served as Interim Director of the Systems Architecting and Engineering Program.

He has over 20 years of management and technical experience in industry including Chief Science Officer at Cost Xpert Group leading the research and development of systems/software estimation and metrics tools, and Chief Scientist at C-bridge Institute where he led consulting and training in software methodologies and economic analysis. Before that he was manager of the Software Engineering Process Group at Litton Guidance and Control Systems achieving SEI CMM Level 4 after being the lead for software metrics, cost estimation and risk management at Litton Data Systems.

He has over 80 publications including the book Software Process Dynamics and is a co-author of Software Cost Estimation with COCOMO II. His research interests include systems and software cost estimation and measurement; modeling and simulation of processes for architecting and engineering of complex software-intensive systems; quantitative methods for systems risk management; integrating systems engineering and software engineering disciplines; process improvement and quality; and integrating empirical-based research with process simulation.

Dr. Wilson Rosa
Air Force Cost Analysis Agency
Wilson Rosa is a Technical Advisor with the Information Technology Division of the Air Force Cost Analysis Agency (AFCAA). Prior to joining AFCAA, Mr. Rosa worked at the Naval Sea Systems Command as a General Engineer where he was responsible for analyzing numerous major acquisition programs including Remote Mine Hunting System, Standard Missile Block IV, Cobra Judy Replacement, Naval Fires Network, and Area Air Defense Commander. Mr Rosa also spent 2 years with the Naval Air Warfare Center (NAWC) as an Industrial Engineer. At NAWC, he prepared multiple budget requests and cost analyses for the V-22 Osprey and T-45 Goshawk project offices. Before joining NAWC, Mr. Rosa was an Engineering Director with Caguas Medical Center (Puerto Rico) where he was responsible for the safety, daily operations, and modernization of 13 regional hospitals.

Throughout his financial management career, Mr. Rosa has received numerous awards and accolades to include 2006 Civilian Cost Analyst of the Year, 2003 Comptroller Excellence Award from the Assistant Secretary of the Air Force (SAF/FM), 2000 Procurement and Competition Excellence Award from the Assistant Secretary of the Navy (ASN/RDA), 2008 Comptroller Eagle Award, and 2003 Runner-Up Civilian Cost Analyst of the Year from the American Society of Military Comptrollers.

Mr. Rosa has recently earned his PhD in Engineering Management at George Washington University (GWU). In 2001, he earned his M.S. in Engineering Management from GWU. He majored in Mechanical Engineering, graduating in 1995 from the University of Puerto Rico.

Thomas Tan
Thomas is a PhD student at the University of Southern California under faculty advisor Dr. Barry Boehm. He is also a research assistant in the Software Cost Estimation Group in the Center of Systems and Software Engineering at USC. His primary research works focus on how application domains and operating environments affect the overall software effort as well as effort distribution patterns. He is also interested in general topic including software cost estimation, software process, and software architecture. In addition of studying as a PhD student, he is also working for IBM as software developer intern in the Rational Method Composer Content Development Team.

Prior to becoming a PhD student, Thomas worked as software consultants at various companies such as LA County Metropolitan Transit Authority, PI Technologies, and Tangram Design. He received his Bachelor of Science degree on Computer Engineering and Computer Science from USC in 2002.