"Under the assumption of no unmeasured confounders, a large literature exists on methods that can be used to estimating average treatment effects (ATE) from observational data and that spans regression models, propensity score adjustments using stratification, weighting or regression and even...

This paper uses Roy's model of sorting behavior to study welfare implication of current health care data production infrastructure that relies on solicitation of research subjects. We show that due to severe adverse-selection issues, directionality of bias cannot be established and welfare may...