Preventing Requirement Defects: An Experiment in Process Improvement

Inadequate requirements cause many problems in software products. This paper reports on an experiment to reduce the number of requirement defects. We analysed the present defects in a real-life product and estimated the likely effect of 44 prevention techniques. We had hoped a novel combination of techniques would come up, but the best approach was quite well known, although new to the company: study the user tasks better, make early prototypes of the user interface, and test them for usability. This approach was tried out in a new development project in the same company. Due to the new approach, there was no doubt about requirements during programming, and as a result it became the first project in the company that was completed on time and without stress. Usability was drastically improved, and as a result the product sold twice as many units as similar products, and at twice the unit price.