Effects of Parameter Uncertainties on Software Development Effort Estimates

Abstract

The Constructive Cost MOdel (COCOMO) for software cost estimation uses inputs of size in lines of code and 15 Development Effort Multipliers (DEMs) that calibrate the estimate to the environment. This study examines the effects of uncertainties, expressed as probability densities of size and DEMs, on COCOMO effort estimates for software developments consisting of more than one Computer Software Configuration Item (CSCI). A Taylor series is used to find the mean and standard deviation of effort in terms of the means and standard deviations of the sizes and the DEMs of the CSCIs. The Central Limit Theorem then enables the evaluation of probability density and cumulative distribution functions for effort. Conditions under which this method is valid are demonstrated.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
May 01, 1990
Accession Number
ADA223304

Entities

People

  • Frederic D. Powell

Organizations

  • MITRE Corporation

Tags

Communities of Interest

  • C4I

DTIC Thesaurus Topics

  • Air Force
  • Classification
  • Computer Programs
  • Cost Models
  • Costs
  • Discrete Distribution
  • Distribution Functions
  • Economics
  • Geometric Forms
  • Information Science
  • Probability
  • Probability Density Functions
  • Probability Distributions
  • Random Variables
  • Software Development
  • Standards
  • Two Dimensional

Fields of Study

  • Computer science

Readers

  • Computer Science.
  • Database Systems and Applications
  • Regression Analysis.