Working Paper: NBER ID: w20708
Authors: Tianyan Hu; Sandra L. Decker; Shinyi Chou
Abstract: We test the effect of the introduction of Medicare Part D on physician prescribing behavior by using data on physician visits from the National Ambulatory Medical Care Survey (NAMCS) 2002-2004 and 2006-2009 for patients aged 60-69. We use a combined DD-RD specification that is an improvement over either the difference-in-difference (DD) or regression discontinuity (RD) designs. Comparing the discrete jump in outcomes at age 65 before and after 2006, we find a 35% increase in the number of prescription drugs prescribed or continued per visit and a 55% increase in the number of generic drugs prescribed or continued, providing evidence of physician response to changes in patient out-of-pocket costs.
Keywords: Medicare Part D; Physician Prescribing; Health Insurance; Drug Coverage
JEL Codes: I13; I18; I31
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Medicare Part D (H51) | increase in the number of prescription drugs prescribed per visit for patients aged 65 and over (I11) |
| Medicare Part D (H51) | increase in the number of generic drugs prescribed per visit for patients aged 65 and over (H51) |
| increase in eligibility for Medicare (I18) | increase in the number of prescription drugs prescribed per visit for patients aged 65 and over (I11) |
| increase in eligibility for Medicare (I18) | increase in the number of generic drugs prescribed per visit for patients aged 65 and over (H51) |
| age 65 cutoff (J14) | eligibility for Medicare (I13) |