 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. We find results suggesting that the implementation of the Affordable Care Act has led to an increase in the hospitalization rate of elderly American--5\% more hospitalization.
<clarity>  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. We find results suggesting that the implementation of the Affordable Care Act has led to an increase in the hospitalization rate of elderly American--5\% more hospitalization.
 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 . Our results suggest that the ACA has (1) led to a 5\% increase in the hospitalization rate of elderly American--5\% more hospitalization.