Learning and Authority: Dynamics of Housestaff Practice Styles
This setting has several advantages. First, training experiences are varied, largely observable, and otherwise as good as randomly assigned. Second, housestaff discontinuously gain authority as they transition from the end of their first year to the beginning of the second year, when they take charge of leading teams as “residents” with new first-year housestaff (“interns”). Fourth, I observe housestaff with widely differing preferences, as expressed by their future specialty commitments (e.g., radiology, dermatology, primary care), performing the same tasks at the same institution and on the same patients.
I find that, despite similar training experiences and essentially no experience prior to residency, housestaff physicians exhibit significant and growing variation in practice styles throughout their training. Due to frequently observed spending data, I impute practice styles within narrowly defined windows of time and also interpret these practice styles as causal, since patients are as good as randomly assigned. I find that interns who are one standard deviation above the mean in spending incur 15-30% higher spending costs. Residents who are one standard deviaationa bove the mean incur 55-80% higher spending costs. The increased variation at least doubles discontinuously as housestaff change informal roles at the end of the first year of training, from “interns” to “residents,” suggesting that physician authority is important for the size of practice-style variation. Practice styles rapidly become more stable over time, as measured by serial correlation in practice styles, especially with greater authority as residents, but somewhat less stable with less frequent practice. This suggests both learning and forgetting of practice styles.
Consistent with highly individualized learning, practice styles are poorly explained by summary measures of training experiences, housestaff observed characteristics (e.g., test scores and demographics), as well as preferences expressed by future training commitments (e.g., future declared radiology vs. primary care training). However, rotating to an affiliated community hospital decreases intern spending at the main hospital by more than half, reflecting an important and lasting effect of institutional norms.