point. Finally, a sufficiently large fraction of the sample and the population will die during our follow-up, leading to “censoring by death”. Those observed to have survived a negative wealth shock include those who would survive under either condition together with those that would survive only if they experienced a negative wealth shock (if any), while those observed to have survived in the absence of a negative wealth shock include those that would survive under either condition together with those that would survive only in the absence of a negative wealth shock. These “missing values” associated with cognition among the deceased are different from the measure of cognition being “missing” due to dropout, where the cognitive ability measure exists but is unobserved. As with wealth shock, death is not a random occurrence, and is positively associated with demographic measures that increase the risk of a negative wealth shock, increased cognitive ability decline, and the experience of a negative wealth shock. Hence, the measure for cognitive ability may be confounded by death if not considered appropriately.

Methods have been developed to deal with these barriers to causal inference. To deal with the lack of randomization, we might hope that, conditional on 