This case study aims to guide research on how to use a dual research method to achieve robust and rigorous results. Both the modeling of structural equations of partial least squares (PLS-SEM) and the comparative qualitative analysis of fuzzy assemblies (fs/QCA) were used in the study that is the basis for this research methods case. Both methods allow the analysis of social phenomena for a small sample. The data were obtained through a questioned Likert-type scale (1-strongly disagree; 7-strongly agree). The study to which this dual methodology was applied aimed to analyze the mediating effect of competitive strategy on the influence of international entrepreneurship on the performance of family businesses. The biggest problem that had to be solved was the calibration of the questionnaire data from the Likert-type scale and checking the consistency of the results obtained: hypothesis comparison for the PLS and confirmation of proposals for the fs/QCA.