Decision-making in requirements engineering often needs to be done in the presence of uncertainty. Rigorous methods can help to increase the probability of making the most appropriate decisions under the given circumstances. Robustness is a measure for the degree of stability of a solution in case of changes in the problem parameters. This paper presents a method (called DECIDERelease) that applies simulation-based analysis and multi-criteria decision analysis on top of the existing strategic release planning approach EVOLVE*. The purpose of DECIDERelease is to qualify decision-making by pro-actively exploring the robustness of the operational plans of upcoming releases. Based on this analysis, the strategic release plan that is the most robust against assumed changes in planning parameters at operational level can be selected. As a proof-of-concept, the applicability of DECIDERelease is demonstrated by an illustrative case study. Results from a survey administered to managers and engineers in industry indicate that the proposed method is perceived as useful in practice.