Questionable necessity effects on suicidal ideation: a commentary on.

Area of Science:

• Psychology
• Mental Health Research
• Statistical Methodology

Background:

• Marchetti et al. advocated for Necessary Condition Analysis (NCA) in mental health research.
• They reported significant necessity effects of perceived burdensomeness and thwarted belonging on suicidal ideation.

Purpose of the Study:

• To scrutinize the findings and conclusions of Marchetti et al. regarding NCA.
• To assess whether necessity effects in NCA can be explained by correlations and potential confounding variables.

Main Methods:

• Estimation of "ranges of spuriousness" (95% confidence intervals for necessity effects).
• Evaluation of necessity effects against expected spuriousness due to variable correlations.
• Analysis of potential confounding impacts by third variables (Z).

Main Results:

• The necessity effects reported by Marchetti et al. fell within the calculated ranges of spuriousness.
• These effects could be accounted for by the correlations between suicidal ideation, perceived burdensomeness, and thwarted belonging.
• The findings challenge the conclusion that perceived burdensomeness and thwarted belonging are necessary for suicidal ideation.

Conclusions:

• The study highlights severe limitations of NCA, particularly regarding the interpretation of necessity effects.
• Researchers using NCA should be aware of potential spuriousness.
• It is recommended to estimate ranges of spuriousness and require necessity effects to exceed this range before concluding necessity.