State surprise billing protections decreased emergency department (ED) out-of-pocket payments to such an extent that ED visits actually increased.
Objectives: The No Surprises Act took effect in 2022 and prevents patients from receiving unexpected emergency department (ED) out-of-network physician bills from in-network hospitals and restricts out-of-network co-payments to in-network co-payment levels. By studying similar state bans, we examine whether the large reduction in out-of-pocket payments under bans will have an unintended consequence of an increase in ED visits and spending.
Study Design: We examine 16 million nonelderly, fully funded, privately insured health maintenance organization (HMO) enrollees between 2007 and 2018 from 15 states with balance billing bans for HMO ED visits and 16 states without bans as the control group.
Methods: Using MarketScan data, we conduct an event study analysis and a difference-in-difference analysis of the impact of state balance billing bans on the probability of an ED visit. We use a 2-part expenditure model to estimate the impact on spending.
Results: By analyzing 15 state-level bans, we find that the bans reduced spending per visit by 14% but spurred a demand response, an increase of 3 percentage points in ED visits, which wiped away the cost savings. Based on an ED severity index, these extra ED visits were 9% less urgent than prior to the bans.
Conclusions: We predict that the federal ban will result in $5.1 billion in savings but 3.5 million more ED visits at $4.2 billion in extra spending per year, largely negating expected savings. Health plans must be prepared to manage this spike in ED visits as the No Surprises Act takes effect.
Am J Manag Care. 2022;28(9):e333-e338. https://doi.org/10.37765/ajmc.2022.89226
For several decades, many hospital patients have faced surprise bills because they have unknowingly used out-of-network providers within in-network hospitals. The insurer covers an “allowed amount,” where the insurer may, for example, pay 70% of that amount, whereas the patient pays the other 30% via a co-payment. However, this allowed amount is often less than what the out-of-network provider charges. The patient must pay the remaining balance of this charge, unless the patient is protected by a state balance billing ban. Often this balance comes as a surprise to patients who did not know that they had used an out-of-network physician at an in-network hospital.
Although 33 states as of 2020 had banned such balance billing,1 under the Employee Retirement Income Security Act (ERISA) of 1974, these state laws do not apply to the millions of Americans with employer-sponsored self-insured plans. Thus, surprise bills were still quite common. For instance, in Texas in 2013, for Humana and UnitedHealthcare patients, 56% and 45%, respectively, of their in-network hospitals had no in-network emergency department (ED) physicians.2 By 2017, 38% of employer-sponsored ED visits in Texas had some out-of-network billing, compared with 18% nationally. In general, in 2018, for those with unexpected bills, the median balance bill was under $500, but 13% owed more than $2000.3 In 2020, fewer than 40% of Americans said they could afford a $1000 surprise bill.4
To extend protections to all states and to workers and their families with self-insured plans, the federal No Surprises Act (NSA) was passed within the Consolidated Appropriations Act of 2021 (Pub L No. 116-260).5 The NSA prohibits ED balance billing everywhere in the United States (including air ambulance bills but not ground ambulance bills).
Recent work has examined how the NSA might affect ED prices. Like most state balance billing laws, the NSA has provisions to resolve out-of-network prices. The act requires an independent arbitration process to determine out-of-network prices, taking into account the median in-network price. The Congressional Budget Office has thus assumed that the act will cause in-network and out-of-network prices to fall to the median in-network price.6 However, there are also concerns that the act may be inflationary with respect to spending.7 Adler found increases in negotiated out-of-network prices after a ban in New York.8 For in-network prices, it is possible that providers will act strategically after the ban to ratchet up the median in-network price to influence the out-of-network arbitration process. Anecdotal reports from physicians under the New York ban indicate that in-network prices increased,9 which contrasts with evidence from at least 1 New York insurer plan in which there was a drop in in-network prices.10 So, the inflationary effect of the NSA on prices is still an unsettled question.
In this article, we instead posit that there may be a much larger, unanticipated inflationary quantity effect of the NSA in terms of increased ED utilization. Indeed, it is well known, especially from the RAND Health Insurance Experiment, that decreasing the out-of-pocket payment for ED visits increases the number of ED visits among the commercially insured.11,12 With the elimination of balance billing and a decrease in allowed out-of-pocket ED amounts, estimated to be as large as $621 per visit by Biener et al, one would expect ED demand to increase significantly under state bans, especially because a majority of Americans have been worried about affording surprise bills.13 In 2018, two-thirds said they were either “very worried” (38%) or “somewhat worried” (29%) about being able to afford unexpected medical bills. One in 10 had a surprise out-of-network bill.14 When states pass bans, they usually receive enormous national and local media coverage. Moreover, plans are required to disclose the new plan changes to the policyholders, particularly about no longer being held liable for balance bills. Thus informed, many individuals are likely to use the ED more often after a state ban. No research has yet estimated this demand effect. In this study, we estimate this effect across 15 state balance billing bans from 2007 to 2018. We focus on commercial health maintenance organization (HMO) ED visits because the earliest wave of state balance bill bans applied only to HMO ED visits. We then discuss demand implications for the 2022 NSA.
Data and Study Population
Much of the recent surprise billing literature on out-of-network visits uses the IBM MarketScan Commercial Claims and Encounters Database from IBM Watson Health.3,15-17 The database assembles insurance claims for approximately 100 medium-sized and large employers and reports actual transaction prices paid by patients and insurers. We extracted all ED claims of nonelderly individuals enrolled in fully insured HMOs from the MarketScan database during 2007 to 2018. Fully insured plans are health plans from which the employees purchase coverage by paying premiums to the plan, and they are covered by state bans. We examine states with at least 5000 ED visits in MarketScan. This gives 16.3 million enrollee-years with 3.8 million ED visits from 31 states: 15 states with balance billing bans for HMO ED visits at some time during the period and 16 states (including the District of Columbia) without bans as a control group (see the eAppendix [available at ajmc.com] for states). Seven of the 15 states with bans use an independent dispute resolution method.18 Four of the states use price benchmarks.19 We identified state bans using several sources.15,19-21
Our goal is to measure the impact of state balance billing bans on (1) the probability of using the ED, (2) the probability of being admitted to the inpatient unit from the ED, (3) annual (allowed) ED spending per person, and (4) the Emergency Severity Index (ESI) of the ED visits. The ESI ranges from 1 (most urgent) to 5 (least urgent) and is a code commonly used by hospitals to triage ED cases, as recommended by the Agency for Healthcare Research and Quality (AHRQ).22 We use the algorithm of Wiler et al to estimate the ESI in our data.23 We also use the AHRQ Clinical Classifications Software to identify common groups of diagnoses under the ESI severity levels.24
We use a difference-in-differences methodology at the enrollee-year level (and at the ED visit level for the ESI analysis), with metropolitan statistical area (MSA)–state fixed effects and SEs clustered at the state level. This difference-in-differences method can sometimes be biased when treatment effects are heterogeneous.25 We check this using the twowayfeweights Stata program of de Chaisemartin et al and verify that our difference-in-differences estimates are not biased because of this issue (eAppendix Table 1).26 Nevertheless, to deal with any potential biases, as suggested by Goodman-Bacon, we further examine the dynamics of the bans using the event study methodology.27 To do this, we focus on the states where we can observe trends both several years before and after the passing of the bans, along with the 16 states without bans. This event study subsample of 21 states consists of 11 million HMO enrollee-years and includes 5 states with bans: California, Connecticut, Illinois, Massachusetts, and Texas. This is a mix of states with differing mechanisms to determine out-of-network prices: regulated prices (benchmarks), independent dispute resolution, hybrid methods, and no prescribed methods.
We also estimate the impact of state bans on annual ED spending per enrollee in the event study subsample using a 2-part expenditure estimator. Finally, as a placebo test, we repeat all our regressions for self-insured HMO plans, which are self-insured by the employer and are exempt from state regulations under ERISA. These plans should not be affected by state balance billing bans (this is confirmed in eAppendix Tables 3 and 5). As a second placebo test, we also run our regressions on Medicare fee-for-service (FFS) ED claims. Medicare has prohibited balance billing since 1997. See the eAppendix for all method details.
In Table 1, we see that the adoption of 15 state balance billing bans for HMO ED visits was associated with an increase in the probability of an ED visit by 2.6 percentage points (P < .05). However, this increase in ED visits had no impact on inpatient admissions from the ED (Table 1). Also, the 15 bans were associated with an increase of 0.27 in the ESI (P < .01), from 3.09 to 3.36 (a 9% increase). Recall that high ESI means low severity. Thus, this result indicates that these extra ED visits due to the ban were 9% less urgent than before the ban.
As a robustness check, we focus on the 5 states that passed bans during 2009 to 2017 so we can analyze what happened before and after the bans compared with the 16 control states without bans. The event study in the Figure shows an increase of approximately 3 percentage points (29% increase) in the probability of an ED visit after the bans, and this effect also remained stable at about 3 percentage points at least 5 years out (P < .01).
Our results may possibly be driven by the reforms of the Affordable Care Act (ACA) during the latter part of our period rather than the balance billing laws. Although the ACA did not prohibit balance billing, it did impose other provisions that may have affected ED visits by altering ED demand and cost structures.28 As a placebo test, we examine the impact of bans on self-insured plans. These plans are exempt from state bans but not from the ACA. We find in eAppendix Table 3 that the 15 state bans did not affect the probability of an ED visit in self-insured plans. In eAppendix Table 5, we see that the state bans had no impact on annual out-of-pocket ED spending in self-insured plans. Thus, our results for fully insured plans are not likely driven by ACA reforms but instead by actual state bans. We also find that the bans did not affect Medicare FFS ED visits (eAppendix Figure 1), as expected because Medicare has prohibited balance billing since 1997.
The parallel trends assumption for our models is shown to hold in eAppendix Table 6. In eAppendix Table 7, several robustness checks are demonstrated. ED visits increase with bans even after controlling for the MSA’s level of physicians integrated with hospitals and for the MSA’s hospital Herfindahl-Hirschman Index. Results are also robust when we leave out 115 MSA-states that had changes in the MarketScan employer composition. Results are robust to potential outlier states using the leave-one-out method, as seen in eAppendix Table 8.29 In eAppendix Table 9, we show that most of the demand effect of bans is because of states with a dispute resolution process,30 a change of 2.6 percentage points vs 1.2 for states without a dispute resolution process.
Despite this increase in the probability of an ED visit after the bans, we do not observe a net increase in annual ED spending per person. In Table 2, we estimate a 2-part model for the 21-state sample. First, the bans increase the probability of an ED visit from 10.8% to 13.8% (P < .01). Next, the bans decrease annual spending on ED visits for individuals with a visit by 14% from $1407 to $1207 (P < .01). Most of this decrease is due to a $148 decrease in annual allowed out-of-pocket spending on the ED (eAppendix Table 5). Hence, the expected spending per person under the bans is $165 (= 0.138 × $1207) compared with $152 (= 0.108 × $1407) without a ban. Thus, the net effect of the bans is an expected increase of $13 per person ($165 – $152). This net effect is not statistically significant. Thus, bans have no impact on ED spending in terms of allowed spending.
Finally, although our data do not have the unallowed balance bill amount, using Medical Expenditure Panel Survey estimates of the unallowed balance billing charge from Biener et al,13 we estimate the mean balance billing charge in our data to be $122 per ED visit (eAppendix). Next, we have estimated the reduced out-of-pocket on the allowed amount to be a mean savings of $148 per ED visit (eAppendix Table 5). Thus, the expected total reduction in out-of-pocket spending per ED visit under the bans is $270 (= $148 + $122). Thus, although there are no overall net savings to society from the bans because of the demand effect, the bans do reduce the expected out-of-pocket cost of an ED visit substantially for the patient.
With such a large reduction in expected out-of-pocket cost of an ED visit, one would expect a possible increase in ED visits after a surprise bill ban, especially with all the media coverage that often surrounds the passage of the ban. Because individuals will no longer have the fear of a possible catastrophic surprise ED bill not covered by their insurer, they may be more inclined to go to the ED in marginal, less severe cases. We estimate an increase of 3 percentage points in ED visits under state bans, with no commensurate increase in inpatient admissions from the ED. We also find that the mean ESI, measured on a scale from 1 (most urgent) to 5 (least urgent), increased by 9% after a ban. These results suggest that this increase in ED visits is indeed composed of less severe, less urgent cases. In fact, we find that the additional ED visits are most often for the diagnosis categories of “sprains and strains” and “superficial injuries; contusions” and less often for the category “nonspecific chest pain.”
Is the size and form of this demand increase reasonable under a $270 decrease in charges per ED visit? Selby et al found that an increase in HMO ED co-payments from $25 to $35 (1993 US$) resulted in a 29% drop in the number of ED visits coded as “often not an emergency.”11 Hsu et al used a natural experiment at Kaiser Permanente HMOs to examine the effect of co-payments on ED use.12 They found that an increase in ED co-payments from $0 to $100 (measured in 2001 US$) reduced ED visits by 23%, or 4.7 percentage points. This is larger than our result but comparable: A $270 decrease in out-of-pocket payments leads to an increase of 3 percentage points (29%) in visits (in 2019 US$).
Our results have implications for the 2022 NSA. We have shown that self-insured plans did not respond to state bans on balance billing, highlighting the potential substantial effect of the federal ban. Previously, some states have attempted to encourage self-insured plans to participate in state-based balance billing regulation. For example, Washington made a significant effort to recruit self-insured employers to voluntarily opt into its 2020 balance billing regulation,31 and New Jersey allowed self-insured plans to opt into the state’s balance billing dispute resolution process in 2018. However, these cases are not typical.32 Our results indicate that the NSA will likely affect many individuals in self-insured plans, as well as those in the states currently without state bans. We estimate this to be approximately 115 million individuals, with 2.4 million a year no longer receiving a surprise out-of-network ED bill (eAppendix).
The NSA will provide these 115 million privately insured adults with substantial additional financial protections. Using Table 2, in which we see that state bans lowered expected allowed annual spending on ED visits by $200 per person using the ED (ie, due to less out-of-network use, lower prices, and the increase in less severe cases), we estimate that the NSA ban would decrease the annual allowed ED spending by $3.2 billion (115 million × 0.138 × $200) a year. Adding in the $122 in balance billing per ED visit, the NSA would save another $1.9 billion per year (115 million × 0.138 × $122). Overall, the NSA will result in $5.1 billion in savings per year ($3.2 billion + $1.9 billion), with a 95% CI of $3.1 billion to $7.1 billion. However, applying the increase of 3 percentage points in ED visits after state bans to the NSA, annual ED spending for the 115 million newly covered will increase by $4.2 billion per year (115 million × 0.03 × $1207), with a 95% CI of $3.9 billion to $4.5 billion, with 3.45 million extra ED visits per year (115 million × 0.03). Therefore, the NSA will result in overall net savings of $900 million ($5.1 billion – $4.2 billion) per year (P = .39), with a 95% CI of –$1.1 billion to $2.9 billion. Thus, our predicted demand response to the NSA is not inconsequential and could wipe away the potential cost savings of the NSA.
How hospitals and insurers deal with this increased ED demand will be of interest. In 2018, to stem ED visits, Anthem began a policy for the commercially insured of not covering ED visits that it deemed, retroactively, to be nonemergent.33 As of July 1, 2021, UnitedHealthcare proposed to begin a similar policy for the commercially insured, although this has been delayed because of its unpopularity.34 Although such retroactive denials would deny approximately 15% of ED visits, they have been shown to be ineffective at reducing the truly unnecessary ED visits.33 Future research should examine better methods of detecting unnecessary ED visits, as well as the new role of urgent care facilities, retail clinics, telehealth, and stand-alone EDs in this environment. Moreover, additional future research should focus on the impact of bans on patient medical debt and bankruptcy.
Our study has several limitations. First, it is not nationally representative. It is biased toward large employers and does not include small employers. Many small firms with fewer than 100 employees are often not self-insured and are covered by state bans. Second, we observe only allowed spending; we cannot estimate the size of balance bills (unallowed charges) and rely on the estimate of Biener et al.13 We presume that state bans eliminated these balance bills, but it is quite possible that some providers still illegally overcharge patients. Finally, our results hold for HMOs, not necessarily for preferred provider organizations (PPOs). Not all the state bans we studied applied to PPOs. Future research should examine PPO patients under the few bans that also applied to PPOs.
We have highlighted an overlooked aspect of the surprise billing literature, as papers so far have failed to account for a demand response to state prohibitions on surprise bills in the ED. We have shown that these bans result in large decreases in out-of-pocket costs for the consumer, which in turn encourages more ED visits for less severe cases after the ban. Because this may also occur more broadly for the 2022 NSA, insurers and primary care physicians may want to renew efforts to prevent costly, avoidable ED visits.
The authors thank Loren Adler, Tom Selden, and Sam Zuvekas for helpful comments.
Author Affiliations: Agency for Healthcare Research and Quality (WE), Rockville, MD; Georgetown University McCourt School of Public Policy (WE), Washington, DC; Peterson Center on Healthcare (KL), New York, NY; University of Pittsburgh School of Public Health (NC), Pittsburgh, PA.
Source of Funding: Agency for Healthcare Research and Quality (AHRQ): AHRQ-IM16513 (to Dr Encinosa); R36-HS027698-01 (to Ms Cornelio). The views expressed in this article are those of the authors, and no official endorsement by HHS or AHRQ is intended or should be inferred.
Author Disclosures: The authors report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.
Authorship Information: Concept and design (WE, KL); acquisition of data (WE); analysis and interpretation of data (WE, KL, NC); drafting of the manuscript (WE, KL, NC); critical revision of the manuscript for important intellectual content (WE, KL, NC); statistical analysis (WE, KL); provision of patients or study materials (WE); obtaining funding (WE, NC); administrative, technical, or logistic support (WE); and supervision (WE).
Address Correspondence to: William Encinosa, PhD, Agency for Healthcare Research and Quality, 5600 Fishers Ln, Rockville, MD 20857. Email: email@example.com.
1. Kona M. State balance-billing protections. The Commonwealth Fund. February 5, 2021. Accessed January 5, 2022. https://www.commonwealthfund.org/publications/maps-and-interactives/2020/nov/state-balance-billing-protections
2. Pogue S, Randall M. Surprise medical bills take advantage of Texans: little-known practice creates a ‘second emergency’ for ER patients. Center for Public Policy Priorities. September 15, 2014. Accessed January 5, 2022. http://forabettertexas.org/images/HC_2014_09_PP_BalanceBilling.pdf
3. Pollitz K, Rae M, Claxton G, Cox C, Levitt L. An examination of surprise medical bills and proposals to protect consumers from them. Peterson-KFF Health System Tracker. February 10, 2020. Accessed January 5, 2022. https://www.healthsystemtracker.org/brief/an-examination-of-surprise-medical-bills-and-proposals-to-protect-consumers-from-them-3/
4. Ostrowski J. Survey: fewer than 4 in 10 Americans could pay a surprise $1,000 bill from savings. Bankrate. January 11, 2021. Accessed January 5, 2022. https://www.bankrate.com/banking/savings/financial-security-january-2021/
5. Fuchs B, Hoadley J. Summary of the No Surprises Act (H.R. 133, P.L. 116-260). The Commonwealth Fund. January 19, 2021. Accessed August 3, 2022. https://www.commonwealthfund.org/sites/default/files/2021-01/Surprise_Billing_Law_Summary_v2_UPDATED_01-19-2021.pdf
6. Estimate for divisions O through FF: H.R. 133, Consolidated Appropriations Act, 2021. Congressional Budget Office. January 14, 2021. Accessed January 5, 2022. https://www.cbo.gov/system/files/2021-01/PL_116-260_div%20O-FF.pdf
7. Hoadley J, Lucia K. Are surprise billing payments likely to lead to inflation in health spending? The Commonwealth Fund. April 26, 2021. Accessed January 5, 2022. https://www.commonwealthfund.org/blog/2021/are-surprise-billing-payments-likely-lead-inflation-health-spending
8. Adler L. Experience with New York’s arbitration process for surprise out-of-network bills. Brookings. October 24, 2019. Accessed January 5, 2022. https://www.brookings.edu/blog/usc-brookings-schaeffer-on-health-
9. Corlette S, Hoppe O. New York’s 2014 law to protect consumers from surprise out-of-network bills mostly working as intended: results of a case study. Georgetown University Health Policy Institute. May 2019. Accessed January 5, 2022. https://chirblog.org/wp-content/uploads/2020/02/Georgetown_StateBased-NY-Billing_May2019.pdf
10. Cooper Z, Scott Morton F, Shekita N. Surprise! out-of-network billing for emergency care in the United States. J Polit Econ. 2020;128(9):3626-3677. doi:10.1086/708819
11. Selby JV, Fireman BH, Swain BE. Effect of a copayment on use of the emergency department in a health maintenance organization. N Engl J Med. 1996;334(10):635-641. doi:10.1056/NEJM199603073341006
12. Hsu J, Price M, Brand R, et al. Cost-sharing for emergency care and unfavorable clinical events: findings from the safety and financial ramifications of ED copayments study. Health Serv Res. 2006;41(5):1801-1820. doi:10.1111/j.1475-6773.2006.00562.x
13. Biener AI, Chartock BL, Garmon C, Trish E. Emergency physicians recover a higher share of charges from out-of-network care than from in-network care. Health Aff (Millwood). 2021;40(4):622-628. doi:10.1377/hlthaff.2020.01471
14. Kirzinger A, Wu B, Muñana C, Brodie M. Kaiser Health Tracking Poll – late summer 2018: the election, pre-existing conditions, and surprises on medical bills. Kaiser Family Foundation. September 5, 2018. Accessed January 5, 2022. https://www.kff.org/health-costs/poll-finding/kaiser-health-tracking-poll-late-summer-2018-the-election-pre-existing-conditions-and-surprises-on-medical-bills/
15. Hoadley J, Lucia K, Schwartz S. Unexpected charges: what states are doing about balance billing. California Health Care Foundation. April 6, 2009. Accessed January 5, 2022. https://www.chcf.org/publication/unexpected-charges-what-states-are-doing-about-balance-billing/
16. Garmon C, Chartock B. One in five inpatient emergency department cases may lead to surprise bills. Health Aff (Millwood). 2017;36(1):177-181. doi:10.1377/hlthaff.2016.0970
17. Chartock B, Garmon C, Schutz S. Consumers’ responses to surprise medical bills in elective situations. Health Aff (Millwood). 2019;38(3):425-430. doi:10.1377/hlthaff.2018.05399
18. Hoadley J, Kona M, Lucia K. States can prevent surprise bills for patients seeking coronavirus care. The Commonwealth Fund. April 29, 2020. Accessed January 5, 2022. https://www.commonwealthfund.org/blog/2020/states-can-prevent-surprise-bills-coronavirus-care
19. Hoadley J, Lucia K, Kona M. State efforts to protect consumers from balance billing. The Commonwealth Fund. January 18, 2019. Accessed January 5, 2022. https://www.commonwealthfund.org/blog/2019/state-efforts-protect-consumers-balance-billing
20. Lucia K, Hoadley J, Williams A. Balance billing by health care providers: assessing consumer protections across states. Issue Brief (Commonw Fund). 2017;16:1-10.
21. Moore R. Surprise Medical Billing in the South: A Balancing Act. Southern Office of the Council of State Governments; 2019.
22. Emergency severity index (ESI): a triage tool for emergency departments. Agency for Healthcare Research and Quality. Updated May 2020. Accessed June 25, 2021. https://www.ahrq.gov/patient-safety/settings/emergency-dept/esi.html
23. Wiler JL, Poirier RF, Farley H, Zirkin W, Griffey RT. Emergency severity index triage system correlation with emergency department evaluation and management billing codes and total professional charges. Acad Emerg Med. 2011;18(11):1161-1166. doi:10.1111/j.1553-2712.2011.01203.x
24. Clinical Classifications Software Refined (CCSR). Healthcare Cost and Utilization Project. Updated October 28, 2021. Accessed January 5, 2022. https://www.hcup-us.ahrq.gov/toolssoftware/ccsr/ccs_refined.jsp
25. de Chaisemartin C, D’Haultfoeuille X. Two-way fixed effects estimators with heterogeneous treatment effects. Am Econ Rev. 2020;110(9):2964-2996. doi:10.1257/aer.20181169
26. de Chaisemartin C, D’Haultfoeuille, Deeb A. TWOWAYFEWEIGHTS: Stata module to estimate the weights and measure of robustness to treatment effect heterogeneity attached to two-way fixed effects regressions. In: Statistical Software Components. Boston College Department of Economics; 2020.
27. Goodman-Bacon A. Difference-in-differences with variation in treatment timing. National Bureau of Economic Research working paper No. 25018. September 2018. Accessed January 5, 2022. https://www.nber.org/papers/w25018
28. Keith K. New regulation justifies previous position on emergency room balance billing. Health Affairs. May 9, 2018. Accessed January 5, 2022. https://www.healthaffairs.org/do/10.1377/forefront.20180509.247998/full/
29. Alsan M, Garrick O, Graziani G. Does diversity matter for health? experimental evidence from Oakland. Am Econ Rev. 2019;109(12):4071-4111. doi:10.1257/aer.20181446
30. Kona M. Map: state laws protecting consumers against balance billing, as of February 5, 2021. The Commonwealth Fund. February 5, 2021. Accessed January 5, 2022. https://www.commonwealthfund.org/sites/default/files/2021-11/Hoadley_balance_billing_state_map_02052021_v2.pdf
31. What consumers need to know about surprise or balance billing. Washington State Office of the Insurance Commissioner. Accessed April 28, 2021. https://www.insurance.wa.gov/what-consumers-need-know-about-
32. Out-of-network Consumer Protection, Transparency, Cost Containment and Accountability Act, A2039 (NJ 2018). New Jersey Assembly Bill 2039. June 1, 2018. Accessed April 28, 2021. https://legiscan.com/NJ/text/A2039/2018
33. Chou SC, Gondi S, Baker O, Venkatesh AK, Schuur JD. Analysis of a commercial insurance policy to deny coverage for emergency department visits with nonemergent diagnoses. JAMA Netw Open. 2018;1(6):e183731. doi:10.1001/jamanetworkopen.2018.3731
34. Haefner M. UnitedHealthcare may not cover ER care it deems nonemergent. Becker’s Payer Issues. June 7, 2021. Accessed January 5, 2022. https://www.beckerspayer.com/payer/unitedhealthcare-may-not-cover-er-care-it-deems-nonemergent.html