Argument-based QUalitative Analysis strategy (AQUA) for analyzing free-text responses in health sciences Delphi...

Delphi methods are mostly used in the health sciences to reach agreement among experts on unclear issues. Generally, consensus is reached after several rounds of Delphi using standardized items. Additional open-ended questions offer respondents the opportunity to provide reasons for judgments. Although these free-text responses contribute substantially to the steering and result generation of the Delphi process, so far no analytical strategy has been established which takes into account the context and methodological principles of the Delphi procedure. Moreover, in already published Delphi studies the analysis of qualitative data is often not sufficiently disclosed.•We provide an overview of analytical strategies for free-text responses. We critically reflect on them with regard to their use and suitability in the context of Delphi procedures.•Following established qualitative methods of qualitative content analysis according to Mayring and thematic analysis according to Braun & Clarke, we developed the Argument-based QUalitative Analysis strategy (AQUA) for Delphi studies in the health sciences and presented it using a concrete project example.•This newly developed strategy can significantly support the rule-governed and intersubjective evaluation of free-text responses in Delphi processes, the integration of the results into the feedback design, and thereby also the quality of the results.