A multiple-case study of software effort estimation based on use case points

Through industry collaboration we have experienced an increasing interest in software effort estimation based on use cases. We therefore investigated one promising method, the use case points method, which is inspired by function points analysis. Four companies developed equivalent functionality, but their development processes varied, ranging from a light, code-and-fix process with limited emphasis on code quality, to a heavy process with considerable emphasis on analysis, design and code quality. Our effort estimate, which was based on the use case points method, was close to the actual effort of the company with the lightest development process; the estimate was 413 hours while actual effort of the four companies ranged from 431 to 943 hours. These results show, that the use case points method needs modification to better handle effort related to the development process and the quality of the code.