Impact of primary care market mergers on quality: Evidence from the English NHS

The primary care market has experienced a growing trend of provider consolidation through mergers and acquisitions, yet the implications of this concentration remain unclear. This study addresses this gap by providing the first empirical evidence on the effects of provider mergers on quality, using evidence from the English primary care market. Examining all provider mergers from 2014 to 2018, we find that mergers improve certain aspects of clinical quality management, but they do not translate into broader population-level clinical quality gains, and patient satisfaction declines significantly. Importantly, the effects vary by merger motivation and the size of the merging parties, rather than their geographic proximity. Survival-driven mergers help sustain care quality and patient access, whereas efficiency-driven mergers lead to greater quality deterioration. Mergers between larger practices also lead to more negative outcomes than those involving smaller practices. In contrast, we find no significant difference between within-market and cross-market mergers. An exploration of the mechanism reveals that changes in market concentration do not explain the observed quality outcomes. Instead, shifts in workforce composition, driven by the underlying merger motivations, play a key role.