Questionable necessity effects on acceptance of surgical robots: A comment on Andrés-Sánchez et al. (2025)

Recently Andrés-Sánchez et al. concluded, based on findings from necessary condition analysis (NCA), that not too low levels of performance expectancy and social influence are necessary conditions for acceptance of surgical robots. However, necessity effects in NCA do not prove necessity as they may be due to zero-order correlations between the analyzed variables. Here, we scrutinized the findings and conclusions by Andrés-Sánchez et al. by estimating “ranges of spuriousness” of effects that can be expected due to correlations between variables. Necessity effects reported by Andrés-Sánchez et al. did not fall above these ranges of spuriousness, meaning that their findings may have been spurious and their conclusions may be challenged. It is important for researchers to be aware that necessity effects in NCA do not prove necessity in order not to overinterpret findings. We recommend researchers to estimate ranges of spuriousness and to require that necessity effects are above this range before claiming that X is necessary for Y. Otherwise, the necessity effect can, as in the present case, be fully accounted for by the correlation between X and Y.