Do hospital mergers reduce waiting times? Theory and evidence from the English NHS

Cirulli V., Marini G., Marini M.A., Straume O.R., 2025 – Journal of Economic Behavior & Organization

Long waiting times are a defining challenge of modern healthcare systems: in 2024, 47% of patients waited more than three months for cataract surgery and 58% for hip replacement. In publicly funded systems with universal coverage, such as the English NHS, the Italian SSN, or the Spanish SNS, excessive delays may push some patients toward private treatments, while others may postpone or forgo care altogether, raising concerns about equity in access.

To tackle the problem of excessively long waiting times, governments have introduced market-oriented reforms to stimulate competition among providers. A prominent example is the internal market in the English National Health Service (NHS), which combines patient choice with activity-based funding to foster hospital competition. The internal market, introduced by the National Health Service and Community Care Act 1990, separated purchasers (health authorities) and providers (hospitals) within the NHS to improve efficiency and quality through competition. However, rather than competing, providers increasingly coordinated their activities, leading to service concentration and, eventually, to formal mergers.

In publicly funded healthcare systems, waiting times are not only a measure of performance but also the main mechanism through which scarce resources are allocated. As a result, merger-induced changes in waiting times have implications beyond efficiency. If waiting times increase, higher-income patients may turn to private care, while lower-income patients remain in the public queue, and some may postpone or forgo treatment altogether. Mergers therefore have important welfare, distributional, and equity consequences.

In a recent article, “Do hospital mergers reduce waiting times? Theory and evidence from the English NHS”, published in the Journal of Economic Behavior & Organization, Vanessa Cirulli, Giorgia Marini, Marco A. Marini, and Odd Rune Straume address this question, both theoretically and empirically. Their findings highlight a crucial insight: the relationship between mergers and waiting times is not straightforward: it depends fundamentally on how hospitals behave and what incentives they face.

Hospital mergers involve two opposing forces. On the one hand, they may reduce costs through economies of scale, improved coordination, and better capacity utilization, potentially lowering waiting times. On the other, they increase market concentration, reduce patient choice, and weaken incentives to attract patients, which may lead to longer queues. The overall effect is therefore theoretically ambiguous.

In publicly funded systems, hospitals compete mainly on non-price dimensions such as waiting times and typically have semi-altruistic objectives, balancing profits and patient welfare. This creates conflicting incentives: hospitals may reduce waiting times to attract patients but also increase them since treating additional patients is often financially unprofitable at the margin. Equilibrium waiting times reflect this trade-off.

Mergers alter these incentives by internalizing competition. Since waiting times are strategic complements, non-merging hospitals adjust in the same direction as merging ones. Mergers combine two opposing effects: altruistic competition, which tends to reduce waiting times, and profit-driven incentives to avoid unprofitable patients, which tend to increase them. The net effect depends on which force dominates.

Finally, if mergers generate cost synergies that lower marginal treatment costs, the scope for reducing waiting times increases. In this case, if hospitals are sufficiently profit-oriented, mergers may lead to lower waiting times for all providers.

Using data on English NHS hospital mergers (2000–2018), the analysis shows that mergers are associated with significant increases in waiting times.

Baseline estimates indicate a rise of about 51% (roughly 30 days relative to a mean of 60), with persistent effects over time, suggesting that reduced competition generally outweighs efficiency gains. Moreover, the effect grows with the duration of exposure. Although the impact of hospital mergers on waiting times becomes statistically significant only from the seventh year after the first merger, it does not diminish over time (Figure 1).

However, the impact is heterogeneous. For less profit-oriented hospitals, waiting times increase substantially after mergers (around 34%, or 21 days), whereas for more profit-oriented providers, such as Foundation Trusts, waiting times tend to decrease, sometimes offsetting the average effect. This pattern supports the theoretical mechanism: when profit-driven incentives and cost synergies dominate, waiting times fall; when altruistic competition prevails, they rise.

Hospital objectives — namely the relative weight placed on profits versus patient welfare — are therefore a key determinant of outcomes. As a result, the effects of consolidation are unlikely to be uniform.

These findings have important policy implications. Merger evaluations should explicitly consider access to care, not only cost efficiency. In regulated-price systems, waiting times are the main dimension of competition and the primary channel through which market structure affects patient outcomes. More broadly, mergers should be assessed within their institutional environment: where incentives are strong, efficiency gains may translate into shorter waiting times; where they are weak, consolidation may instead reduce access.

These results are highly relevant for the current Italian policy debate, where concerns over long waiting times coexist with hospital reorganization and the expansion of community-based care under the PNRR. While mergers and service concentration are often justified by efficiency gains, our findings suggest caution: without strong incentives and accountability, reduced competition may lead to longer waiting times. At the same time, the shift toward territorial healthcare (case della comunità, telemedicine, integrated care) may ease pressure on hospitals, but only if effectively coordinated with hospital capacity and referral systems; otherwise, bottlenecks may persist. More broadly, the Italian case highlights the need to align organizational reforms with incentives. As in the English NHS, waiting times are not just an outcome but a key rationing mechanism, making their reduction central to both efficiency and equity.