The Effect of Software Size Uncertainty on Effort Estimates Generalized by Alpha Times I to the Beta Power Software Resource Models.

• Main Author: Garvey, Paul R
• Other Authors: MITRE CORP BEDFORD MA
• Format: Text
• Language: English
• Published: 1987
• Subjects: Computer Programming and Software; *COMPUTER PROGRAMS; COST ESTIMATES; DISTRIBUTION; EQUATIONS; IMPACT; MATHEMATICS; MODELS; PROBABILITY; SIZES(DIMENSIONS); VARIATIONS; STATISTICAL ANALYSIS; MATHEMATICAL MODELS; NADS(North Atlantic Defense System); ASEP(Analytic Software Effort Probability); LPN-Mitre-443C; Mitre; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA189209; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA189209

In support of the Cost Technical Center's estimate of the North Atlantic Defense System (NADS) software development effort, a new probability model, the Analytic Software Effort Probability (ASEP) model, has been developed that quantifies the impact of software size uncertainty on effort estimates generated by Alpha I Beta software resource models. This paper provides the mathematical foundation of the ASEP model. Analytic equations that yield the exact density, cumulative distribution, mean, and variance of the development effort, given that the size of a single Computer Software Configuration Item(CSCI) is a uniform or triangularly distributed random variable, are described. These equations are extended to the case of approximating the overall development effort mean, variance, and distribution for a system consisting of multiple CSCIs.