Before revision:  Using the data from the National Health Interview Survey (NHIS) , we apply this  identification strategy to evaluate the causal effect of the Affordable Care Act (ACA) on  health care access and utilization of old Americans.
After revision:  The point estimates of the treatment effect using a simple fuzzy difference-in-discontinuities design are biased if the change in the probability of a treatment applying at the cutoff differs across treatments. Modifications of the fuzzy difference-in-discontinuities approach that rely on milder assumptions are also proposed. Our results suggest caution is needed when applying before-and-after methods in the presence of fuzzy discontinuities. Using data from the National Health Interview Survey (NHIS) , we apply this identification strategy to evaluate the causal effect of the Affordable Care Act (ACA) on health care access and utilization of old Americans.