Decision on SIG-2026-0128

[MSOM Conference]

08-May-2026

Re: SIG-2026-0128, "The Effects of Hospital-Physician Integration on Patient Access"

SIG Day Decision: Reject

Dear Author (this is to ensure anonymity):

We received many excellent submissions for the Healthcare Operations Management SIG-Day Conference. Unfortunately, we could not accept all of them to be included in the program, and we are sorry to say that your paper was not accepted to the SIG-Day conference.

If you also submitted an extended abstract of your paper to the main MSOM Conference, a decision on that submission will be made separately.


Sincerely,

Healthcare Operations;SIG Co-Chairs

MSOM Healthcare Operations Management SIG-Day Co-Chair

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Referee: 1
Strengths SIG Only: The paper investigates a well-studied problem, hospital-physician integration in US, through a new angle: its impact on access to care for non-commercially insured (e.g. Medicare and Medicaid) patients. The problem is relevant and important, and the data is detailed. The analysis is conducted with care.

Referee: 2
Strengths SIG Only: The important strengths are the relevance of the research question, data collected, analysis, usning game theory to develop hypothesis, and overall writing of the paper.

Referee: 3
Strengths SIG Only: The paper studies a timely question that is highly relevant to policymakers debating whether to allow the types of mergers rapidly occurring in the healthcare space. It combines a game-theoretic modeling with difference-in-differences empirical approaches using a comprehensive dataset. The results are meaningful, showing a substantial increase in elective admissions after integration with the increase being concentrated among non-commercially insured patients. This may represent an underserved group that now has better access due to market dynamics, suggesting that policymakers should actually be encouraging, and not hindering, such activities.

Referee: 1
Limitations: 1. A primary concern is whether the observed increase in admission volumes truly represents improved "access" or simply a shift in referral patterns, often called "keepage" in the literature. The paper uses physician-level inpatient admission volume as a proxy for access. However, this is an equilibrium quantity outcome that may reflect a hospital's increased market power to "steer" patients into its own facilities once a physician/practice is integrated.

While the authors attempt to insulate the analysis from bias by measuring admissions at the physician level independent of the specific hospital, they do not fully eliminate the possibility that integrated physicians are simply prioritizing inpatient admissions within their own high-cost systems over other lower-cost outpatient alternatives that are no longer financially incentivized.

2. The paper frames the increase in non-commercial volume as a "subsidy" provided by higher commercial prices. This interpretation overlooks significant negative externalities for the Medicare and Medicaid programs. The literature cited in the paper consistently find that integration leads to various additional fees which increase spending for Medicare and Medicaid without necessarily improving quality. And increased quantity at a more expensive site of care (integrated hospitals) may be "bad" for the overall health system. The paper lacks the analysis to determine if the "access" gained justifies the increased financial burden on Medicare/Medicaid programs and the higher out-of-pocket costs for beneficiaries.

3. The study identifies that integrated physician contracts are primarily based on work Relative Value Units (wRVUs), which are volume-based productivity incentives independent of payor. In this case, the 9.9–12.8% increase in elective volumes found in the paper may not be fulfilling an "unmet need" but could instead reflect supplier-induced demand. Physicians paid on wRVUs have a direct financial incentive to admit more patients to the inpatient setting regardless of medical necessity.

More importantly, without matching these increased volumes to clinical outcomes—which the paper admits is an inconsistent metric in previous literature—it is difficult to distinguish better access from medical over-utilization.

4. The paper notes that integration is "endogenously selected" into by both parties. As a result, hospitals may specifically target physicians for integration who have the highest potential for increasing overall volume to increase revenue.

The assumption that contracts are payor-agnostic might also be endogenous. Systems might selectively offer RVU-based contracts to certain specialties or regions to optimize their own internal cross-subsidization strategies, which makes the current Difference-in-Differences strategy invalid.

5. The use of Florida data from 2010–2020 introduces specific regional biases and may limit the study's generalizability: Florida is a premier retirement destination, leading to a natural and rapid increase in the Medicare-eligible population during the study window.

While the authors use emergency patients to control for population shifts, these controls may not perfectly capture the specific geographic and demographic trends within Florida. If integrated systems are more prevalent in rapidly aging counties, the "access" found could simply reflect local demographic growth.

Referee: 2
Limitations: There are no major limitations. However, the authors could consider adding heterogeneous effects beyond the market variable.

Referee: 3
Limitations: In studying an ambitious question, the paper runs up against a few limitations. On the empirical side, the authors are careful to interpret their findings as associations. However, there are a number of alternative explanations, such as changes in patient routing, workload reallocation, and other post-integration organization changes, that account for growth in volume other than access expansion. Using the pre-integration commercial terciles as a proxy for profit orientation may capture service mix (e.g. more profitable line in for-profits) or other structural differences. As a minor point, the interpretation drawn from Figure 4 may be a bit strong without showing that there are significant differences between HHI levels.

From the modeling perspective, the central assumption is that integration removes any exposure that physicians have to the payor. This is examined extensively in Appendix B. However, it does not account for the fact that integrated physicians may still face indirect pressure from hospitals on profitability. For example, physicians are often pressured to keep referrals in-house. They may also be required to bill a certain number of RVUs, which indirectly affects their own wages through patient selection. Additionally, treating the admissions decision as solely a physician decision may be an oversimplification. Insurers, to name another party, also likely have significant sway over elective admissions through prior authorizations, medical-necessity reviews, and other criteria.

Referee: 1

Comments to the Author
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Referee: 2

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Referee: 3

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