"Observational studies" of demand for medical care (i.e.. those simply observing individuals' behavior) have often found

[answerhappygod]

"Observational studies" of demand for medical care (i.e.. those
simply observing individuals' behavior) have often found demand
elasticities for individuals' use of care that are quite large, in
the neighborhood of -1 or larger. Quasi-randomized trials and
randomized controlled trials have found much smaller elasticities
(closer to zero). Discuss the hazards and strengths of using
observational studies vs. randomized trials to learn the true
effect of health insurance on demand for medical care