Target trial emulation shows that supported causal effects of religious attendance on well-being are selective

Religious service attendance is associated with better well-being, but observational associations do not establish causation. We analyse six annual waves of the New Zealand Attitudes and Values Study () to estimate causal effects of monthly attendance on 24 well-being indicators using target trial emulation. Deterministic 'make everyone attend' contrasts fail positivity: only 2-3% of non-attenders initiate attendance per year. We therefore estimate supported stochastic interventions () among baseline non-attenders () using a sequentially doubly robust estimator with cross-validated machine learning. Effects are selective: small gains appear in meaning and purpose, forgiveness, and sexual satisfaction, with little movement in somatic health, psychological distress, social belonging, or perceived social support. A comparison exposure (+1 hour per week socialising with others) does not reproduce the pattern. We interpret the selective pattern through a prominent cooperative account of religion: gains concentrate in coordination-relevant domains rather than in direct health pathways.