Barry Boehm

Barry W. Boehm ( born May 16, 1935 in Santa Monica, California ) is an American software engineer, who was known for his cost considerations of large software projects. He saw software as the primary cost factor for future information technologies. So he invented the COCOMO software costing, risk - and cost-saving approach - spiral model and, inter alia, an advanced Delphi method ( wideband delphi ). He was involved as a consultant and as a researcher with many military and civilian large-scale projects.

Boehm made ​​in 1957 from Harvard University with a bachelor's degree in Mathematics, 1964, he received his doctorate at the University of California, Los Angeles for PhD in mathematics. After that, he worked for many years as a teacher and researcher. Later he was a consultant for the company RAND Corporation, TRW and DARPA. Today he is Professor of Software Engineering, Computer Science, at the University of Southern California (USC ).

Software cost estimation with COCOMO method

COCOMO (81 )

COCOMO is an algorithmic model for cost and effort estimation for the development of computer programs. The effort (measured in Staff Month ( 152 hours ) ) is calculated on the basis of statistical calculation methods on collected data of past projects, depending on the software size, which in Delivered Source Instructions ( DSI) is measured. According to size COCOMO divided the projects into three groups. The calculation of the expense is in three levels of detail, with the simplest model to deliver an even more rough estimate:

  • K = constant scaling coefficient for the effort
  • P = This exponent represents the savings magnification production (economies of scale ); especially the savings by avoiding non-value -generating activities (eg, idle time, delays, communication overhead, etc.)

The other calculation models include with each different cost factors (eg experience of programmers, quality requirements of the software, etc.) and divide the project into several sub-components as well as the project in different phases. Thus COCOMO reached a relatively high degree of accuracy.


ADA COCOMO is a further development of COCOMO 81 - which is very strongly influenced by batch processing and the waterfall process model - to adapt to the TRW implementation of the ADA process model. This model includes risk management, architecture Skeletons, incremental implementation and testing and standardized software metrics. Main focus of the model are to reduce the communication overhead, avoid late reworking due to unstable requirements.


COCOMO II was also, like its two predecessors, developed by Barry W. Boehm and the first time in 1997 published. The official version is known, however, been published in 2000 with the book Software Cost Estimation with COCOMO II. COCOMO II represents the changes in the " modern" software development. There are again, as distinguished 81, three different types of estimation in COCOMO, however, that these refer to the difference increased to the level of development of the project, however, is to dispense with the division on the project size.

The process model spiral model

Boehm developed from extensive experience out a new process model for software development. This spiral model is to reduce by spirally, repeated viewing of the phase results, the risk of failure. The spiral model has influenced many subsequent process models.

Wideband Delphi

Boehm refined the Delphi method and called this refined method Wideband Delphi. So it was applicable for a larger area.


He is a Fellow of the AIAA, the ACM and the IEEE. He is also a member of the National Academy of Engineering.