Practical challenges of requirements prioritization based on risk estimation

Requirements prioritization and risk estimation are known to be difficult. However, so far, risk-based requirements prioritization has not been investigated empirically and quantitatively. In two quantitative experiments, we explored practical challenges and needs of risk estimations in general and of our method MOQARE specifically. In the first experiment, ten students made individual estimations. In the second one, twenty-four students estimated risks in seven moderated groups. The students prioritized the same requirements with different methods (risk estimation and ranking). During the first experiment, we identified factors which influence the quality of the prioritization. In the second experiment, the results of the risk estimation could be improved by discussing risk estimations in a group of experts, gathering risk statistics, and defining requirements, risks and prioritization criteria more tangibly. This first quantitative study on risk-based requirements prioritization helps to understand the practical challenges of this task and thus can serve as a basis for further research on this topic.