Scientific claims, and the way they are tested, must be unambiguous and flexibility must be disclosed. Grounded in Popper’s principle of falsification, we suggest the Falsification Assessment Form (FAF). The form aims to identify ambiguity and undisclosed flexibility in the entire research process with 11 items covering hypothesis formulation, data processing, analysis, and alternative explanations. It also collects information on transparency measures, such as preregistration. The form was developed through consensus among the authors and refined via a collaborative feedback assessment of 19 experts. It is intended for original, quantitative research, it highlights potential issues and requires authors to provide detailed responses. FAF is meant to be a structured qualitative audit framework. It can be used to identify concerns in published research, improve the quality of papers during peer review, or guide rigorous study planning from the outset. We open up further refinement and testing of FAF to the scientific community.