|Title||What We Do and Don't Know About Software Development Effort Estimation|
|Afilliation||, Software Engineering|
|Publication Type||Journal Article|
|Year of Publication||2014|
OVERWHELMING EVIDENCE DOCUMENTS a tendency toward cost and effort overruns in software projects. On average, this overrun seems to be around 30 percent.1 Furthermore, comparing the estimation accuracy of the 1980s with that reported in more recent surveys suggests that the estimation accuracy hasn't changed much since then. Estimation methods haven't changed much either. In spite of an extensive research on formal estimation models, the dominating estimation method is still expert estimation. An apparent lack of improvement in estimation accuracy doesn't mean that we don't know more about effort estimation than before. In this article, I try to summarize some of the knowledge I believe we've gained. Some of this knowledge has the potential of improving the estimation accuracy, some is about what most likely will not lead to improvements, and some is about what we know we don't know about effort estimation.