We found that better quality of care provided to community-dwelling vulnerable older persons was associated with higher 3-year survival. The relationship between quality of care and survival was robust to analysis in several different ways. The process–outcome link remained after weighting for quality score stability and after adjustment for quality indicator difficulty. The alternative explanation, that physicians elect to provide less care to persons on a downward trajectory, is less likely because we did not observe a relationship between care quality and sickness or age. Although our study is observational, our results satisfy most of the factors explicated by Hill (17) for making causal inference in observational studies, the most important of which are strength of association, temporality of the cause and effect, the presence of a dose–response gradient, plausibility of causal mechanisms, coherence with current knowledge, consistency with other studies, and specificity of the association. Our finding of a moderately strong association between process and outcome has no temporal ambiguity between process and outcome, with evidence of a dose–response relationship, and a plausible mechanism of effect that is consistent with current knowledge. Only consistency and specificity of the association are not satisfied by our results. Consistency cannot be tested by only 1 study, and specificity cannot be tested because our only outcome measure is mortality. Furthermore, the formal sensitivity analysis for a potential unmeasured omitted confounder revealed that this confounder must be very strongly related to both quality and survival to explain the quality–survival relationship beyond the adjustment for other covariates. Therefore, we believe that the most plausible interpretation of our results is that the receipt of better-quality care was causally linked with improvement in 3-year mortality in our sample of community-dwelling vulnerable older adults.