The Comparison and Improvement of Effort Estimates from Three Software Cost Models

Kafura, Dennis G. and Henry, Sallie M. and Gintner, Mark (1987) The Comparison and Improvement of Effort Estimates from Three Software Cost Models. Technical Report TR-87-37, Computer Science, Virginia Polytechnic Institute and State University.

Abstract

This paper presents an empirical investigation of effort estimation techniques using three software cost models: Boehm's basic COCOMO model, Thebaut's COPMO model, and Putnam's model. The results, based on proprietary historical project data provided by a major computer manufacturer, are in three parts: (1) a comparison of the three mdels showing that more accurate estimates are obtained from the COPMO model; (2) improvements in the COPMO estimates by means of two techniques termed "submodeling" and "constructive modeling"; and (3) the definition and evaluation of a promising new technique, termed "adjustment multipliers", for improving a model's estimates. Finally, a second set of industrial data is used to confirm the general applicability of these improvement techniques.