What We Do and Don´t Know about Software Development Effort Estimation

Unrealistic project plans and cost overruns create problems for software professionals and their clients. In spite of much research and numerous attempts to learn from experience, the problem of inaccurate, frequently overoptimistic cost estimates hasn´t been solved. This article summarizes some knowledge that could improve the estimation accuracy, but we still lack some knowledge that hinders us from being able to produce accurate estimates.