Does practice make perfect? Panel evidence from hip fracture surgery in Italy

A large body of evidence documented a positive association between hospital volume and patient outcomes, but the underlying causal mechanisms remain debated. While the "practice makes perfect" hypothesis suggests quality gains from centralization, the "selective referral" hypothesis raises concerns about access and equity.

To examine the causal effect of surgical volumes on outcomes for hip fracture patients in a non-competitive healthcare system. In this setting, patients are routinely referred to the nearest hospital for urgent surgeries, and mandatory minimum-volume thresholds have been in place since 2016. These institutional features offer a robust context to test the "practice makes perfect" hypothesis.

The analysis is based on a cohort of emergency patients admitted to publicly funded hospitals in the Emilia-Romagna region of Italy between 2017 and 2019, after implementation of Ministerial Decree DM70/2015, which introduced volume thresholds for hip fracture surgeries. Using multi-way fixed effects models and a comprehensive set of covariates to control for confounders, we estimate the causal effect of surgical volumes on 30-day mortality.

Our findings document a robust volume-outcome relationship: higher lagged surgical volumes are significantly associated with lower 30-day mortality rates. The fact that the effect strengthens with longer lag periods is consistent with a learning-by-doing mechanism, whereby accumulated experience improves outcomes.

In non-competitive systems, volume-based standards for urgent procedures are associated with better outcomes and provide a rationale for further centralization, as long as ensuring universal access remains central.