Issues affecting the reliability of software-cost estimates (trying to make chicken salad out of chicken feathers)

The author discusses a wide range of dynamic factors (many of which are managerial, subjective, and/or nonquantifiable) present in the software development environment that severely inhibit the generation of reliable cost estimates. The wide-ranging results of a comparison of several cost models applied to a hypothetical system are presented to illustrate the basis for low confidence levels in software cost estimating methodologies. Results of a recently conducted empirical application of emerging software size estimation models are also presented