Practical guidelines for expert-judgment-based software effort estimation

This article presents seven guidelines for producing realistic software development effort estimates. The guidelines derive from industrial experience and empirical studies. While many other guidelines exist for software effort estimation, these guidelines differ from them in three ways: 1) They base estimates on expert judgments rather than models. 2) They are easy to implement. 3) They use the most recent findings regarding judgment-based effort estimation. Estimating effort on the basis of expert judgment is the most common approach today, and the decision to use such processes instead of formal estimation models shouldn't be surprising. Simple process changes such as reframing questions can lead to more realistic estimates of software development efforts.