Software effort estimation terminology: The tower of Babel

It is well documented that the software industry suffers from frequent cost overruns. A contributing factor is, we believe, the imprecise estimation terminology in use. A lack of clarity and precision in the use of estimation terms reduces the interpretability of estimation accuracy results, makes the communication of estimates difficult, and lowers the learning possibilities. This paper reports on a structured review of typical software effort estimation terminology in software engineering textbooks and software estimation research papers. The review provides evidence that the term ‘effort estimate’ is frequently used without sufficient clarification of its meaning, and that estimation accuracy is often evaluated without ensuring that the estimated and the actual effort are comparable. Guidelines are suggested on how to reduce this lack of clarity and precision in terminology.