Do concern mining tools really help requirements analysts? An empirical study of the vetting process.

•Empirical evaluation of concern vetting with 55 subjects in 3 systems and 3 tools.•Time does not have an effect on the final quality achieved by analysts.•The initial quality of a solution is a crucial factor to achieve satisfactory results.•The concern mining tools exhibited performance variations, although they were not statistically significant in our case-studies.•Analysts work best using solutions with high recall rather than with high precision.