A CAUSAL MODEL FOR SOFTWARE COST ESTIMATING ERROR

Software cost estimating is an important concern for software managers and other software professionals. The hypothesized model in this rese arch suggests that an organization's use of an estimate influences its estimating practices which influence both the basis of the estimating process and the accuracy of the estimate. The model also suggests tha t the estimating basis directly influences the accuracy of the estimat e. A study of business information systems managers and professionals at 112 different organizations using causal analysis with Equations Mo deling System (EQS) refined the model. The refined model shows that no managerial practice in this study discourages the use of intuition, g uessing, and personal memory in cost estimating. Although user commitm ent and accountability appear to foster algorithm-based estimating, su ch an algorithmic basis does not portend greater accuracy. Only one ma nagerial practice-the use of the estimate in performance evaluations o f software managers and professionals-presages greater accuracy. By im plication, the research suggests somewhat ironically that the most eff ective approach to improve estimating accuracy may be to make estimato rs, developers, and managers more accountable for the estimate even th ough it may be impossible to direct them explicitly on how to produce a more accurate one.