 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.
<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.
 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 older Americans' health care access and utilization of old Americans.