بیمه سلامتی به عنوان یک قرارداد قیمت گذاری دو بخشی

Monopolies appear throughout health care. We show that health insurance operates like a conventional two-part pricing contract that allows monopolists to extract profits without inefficiently constraining quantity. When insurers are free to offer a range of insurance contracts to different consumer types, health insurance markets perfectly eliminate deadweight losses from upstream health care monopolies. Frictions limiting the sorting of different consumer types into different insurance contracts restore some of these upstream monopoly losses, which manifest as higher rates of uninsurance, rather than as restrictions in quantity utilized by insured consumers. Empirical analysis of pharmaceutical patent expiration supports the prediction that heavily insured markets experience little or no efficiency loss under monopoly, while less insured markets exhibit behavior more consistent with the standard theory of monopoly.

Fully insured patients face health care that is free at the margin. This leads to over-consumption of costly health care resources. As a result of this “moral hazard,” optimal health insurance contracts balance the need for insurance against the need for more efficient utilization incentives (Arrow, 1963; Pauly, 1968; Zeckhauser, 1970). This balance explains why health insurance contracts often charge an ex post unit price or co-payment, in addition to an upfront premium. Co-payments reduce the degree of insurance, but in return limit the extent of over-consumption, because the consumer faces an out-ofpocket price that partially reflects social cost. Much attention has been paid to the optimal design of these “two-part” health insurance contracts that charge a premium and an ex post co-payment. The emphasis has been on how to manage moral hazard and other insurancemarket failures like adverse selection. However, two-part health insurance contracts might have another function that is less appreciated: the reduction of deadweight loss from market power among health care providers. Our central hypothesis is that health insurance resembles a two-part pricing contract in the sense that consumers pay an upfront fee (premiums) in exchange for lower unit prices (co-payments) in the event of illness. Outside the health insurance context, standard theory implies that two-part pricing contracts allow a monopolist to sell goods at marginal cost, but to extract consumer surplus in the form of an upfront payment (see the seminal paper by Oi, 1971). The standard normative prediction is that two part pricing contracts provide a monopolist the same incentives to minimize deadweight loss as a competitive market. Intuitively, deadweight loss-minimization by the monopolist maximizes the total consumer surplus available for the firm to extract in the form of an upfront payment. An example illustrates the hypothetical analogy between health insurance and a two-part pricing contract. Imagine a monopolist that produces health care and provides health insurance. By setting its co-payment equal to marginal cost, this monopolist can ensure that consumers use care efficiently and thus derive the greatest possible gross consumer surplus from its use. The monopolist can then profit from this strategy by charging an upfront premium equal to this gross consumer surplus. Under this arrangement, consumers remain willing to participate in the health insurance market, utilization occurs at the efficient levelwheremarginal cost equalsmarginal benefit to consumers, and the firm earns profits equal to gross consumer surplus. This is the usual logic through which two-part pricing generates maximum profits and first-best utilization. Of course, it is not immediately obvious whether the logic in this simple example extends to the realities of the health care marketplace, which involves the interaction of disintegrated insurers and providers, heterogeneous consumers, and awide range of information asymmetries.In this paper,we study the applicability of the two-part pricing hypothesis to health care and reach two primary conclusions: • When different types of consumers can sort into different types of insurance contracts, health insurance markets perfectly eliminate deadweight loss from market power in health care provision. This logic is robust to moral hazard, adverse selection, the disintegration of providers and insurers, and two-sided market power for providers and insurers. • When perfect sorting of consumers is not possible, deadweight loss from powerful health care providers creates uninsurance, but does not generate under-utilization of medical care by insured consumers.1 Insurers forced to charge “pooled” uniform premiums to a diverse set of consumers may decide to sell to the highest-demand consumers only, and to price marginal consumers out of the insurance market entirely. However, even under this scenario, insurers still have incentives to encourage efficient utilization among the consumers who remain insured. Our results have several implications for policymakers seeking to limit deadweight loss due to market power in health care. First, the extent and even presence of deadweight losses from health care monopoly are determined by the structure of the insurance market. For example, the extent of premium-discrimination in the health insurance market determines the degree of monopoly loss suffered in the hospital market, even when hospitals do not themselves sell insurance. Therefore, the decision to regulate or allow monopoly in health care provision should be informed by the structure of the health insurance market. Moreover, policies that expand insurance coverage or promote efficiency in the insurance market may be viewed as substitutes for regulating monopoly in health care provision. Second, the price–cost margin for health care goods is an unreliable measure of welfare loss from monopoly power. When insurance is widespread and reasonably complete, providers may be receiving very high monopoly prices and profits, even though consumers are paying prices near or even below marginal cost. The copayment–cost margin is a similarly inconsistent measure of welfare loss from monopolies, as it is driven primarily by the extent of moral hazard and not by the monopoly power of upstream providers. The two-part pricing view of health insurance leads to two testable empirical implications that differentiate it from alternative theories. First, eliminating health care monopolies in heavily insured markets will lead to little or no change in the quantity of health care consumed, because consumer copayments will be insensitive to market power among providers. In contrast, eliminating health care monopolies in largely uninsured markets will increase the quantity of health care used and reduce deadweight loss as prices fall from monopoly levels to marginal cost levels. Second, the two-part pricing theory uniquely implies that the absolute value of demand elasticities under monopoly may be greater than unity. Empirical analysis of patent expiration in the pharmaceutical market provides evidence consistent with these positive predictions. The elimination of pharmaceutical patent monopoly has little to no impact on quantity consumed for molecules that are heavily insured, but substantial quantity impacts for molecules with less widespread insurance. In addition, demand elasticities in less-insured markets follow the predictions of standard monopoly models, while elasticities in heavily insured markets are consistent only with a two-part pricing interpretation. The paper proceeds as follows. Section 2 develops the analogy between health insurance and the standard theory of two-part pricing, even when information is incomplete and market power imperfect. Section 3 presents our empirical analysis. Finally, Section 4 summarizes our conclusions and implications for the analysis of market power in health care.

The presence of health insurance alters the welfare analysis of monopoly. Price–cost margins and even copayment–cost margins become unreliable yardsticks of welfare loss, which is more reliably measured in terms of reductions in quantity or marginal increases in rates of uninsurance. Analysis of pharmaceutical markets provides positive evidence consistent with the theory, since drug therapies with less insurer presence exhibit greater deadweight loss from monopoly and greater gains from the elimination of market power. On the other hand, drugs with greater insurer presence seem to gain less, if they gain anything at all, from reductions in market power. They also seem to be priced off the consumer demand curve in ways that are inconsistent with alternative theories of monopoly under insurance. From a normative point of view, our theory predicts that healthcare monopoly leads to efficiency losses from higher rates of uninsurance, but does not affect efficiency for insured consumers. This implies that greater penetration of health insurance lowers the deadweight loss associated with market power in health care provision. In the polar case of full insurance, market power among providers is entirely a distributional rather than efficiency issue. More generally, policies that expand health insurance take-up can limit the deadweight loss from market power, without direct regulation of health care providers. In sum, a well-functioning and complete insurance market transforms the problem of health care market power from one of deadweight loss into one of distribution. The design of public health insurance often considers the trade-offs among optimal risk-bearing, moral hazard, and adverse selection. However, our analysis suggests that it ought to consider how a two-part health insurance contract can bestmaximize social surplus. An optimally designed public health insurance scheme would set co-payments at or belowmarginal cost, depending on the extent ofmoral hazard. The division of resources among consumers can then be determined by the schedule of premia, which allows the government to extract (and then redistribute) as much or as little consumer surplus as it chooses. In markets where innovative products are sold, two-part health insurance can also be configured to generate any desired change in the profits that serve as the incentive for innovation, without compromising static efficiency in the utilization of health care goods (D. Lakdawalla and N. Sood, 2009). For example, setting premiums so that providers keep more profit will stimulate greater innovation, and vice-versa. Critically, these incentives for innovation can be manipulated without affecting the efficiency of utilization, which is governed by copayment levels. The normative implications of the theory lead to several important lessons for policymakers. First, new approaches are needed for identifying the presence of inefficient market power in health care. Specifically, high price–cost margins in healthcare are not sufficient indicators of deadweight loss from market power. The theory predicts that when all consumers are insured, high price–cost margins do not create deadweight loss. Even copayment–cost margins are insufficient indicators, as these reflect the degree of moral hazard, rather than deadweight loss from health care provider market power. Anti-trust enforcers, courts, and policymakers should instead look for high price–cost margins coupled with high or rising rates of uninsurance. These are more reliable signs of deadweight loss. To our knowledge, the take-up of insurance is rarely if ever taken into consideration by courts or anti-trust enforcement agencies. This practice should be revisited. Second, from a deadweight loss perspective, healthcare anti-trust enforcement is less valuable in markets with full insurance or high levels of insurance. More generally, antitrust enforcement in insured markets is purely redistributive, and should thus be compared against other policy options for redistribution like taxation and subsidies. To be specific, in an insured marketplace, “letting monopoly stand” might be no different than breaking it up, except in terms of distributional impacts. Therefore, the scope and aggressiveness of antitrust policy should turn on society's preferred approach to distribution, rather than on its approach to efficiency. Third, when evaluating aggressive anti-trust in healthcare, policymakers should be comparing it to alternative distributional policies, rather than treating it as a unique tool for promoting efficiency. For example, the social costs and benefits of antitrust enforcement should be compared to the costs and benefits of taxing the profits of powerful health care providers, making transfers to poorer health care consumers, and related policies. This contrasts with the typical approach, which primarily compares the virtues of monopoly to the virtues of competition— e.g., the valuable scale economies of large firms might be compared to the price-discipline of competition between small firms. Fourth, there is a unique efficiency rationale for policies that expand the take-up of health insurance, when health care providers possess market power. In this case, greater insurance take-up lowers deadweight loss due to market power. As a corollary to this point, health insurance expansion can be viewed as a policy substitute to antitrust enforcement. Indeed, in a marketplace where health policy guarantees universal coverage, there is much less, or perhaps even no, efficiency gain from anti-trust enforcement against healthcare providers. Significantly, policy discussions surrounding health insurance expansions often focus on equity issues, or perhaps even health spending issues, but they often fail to consider the value of health insurance expansions for more efficient healthcare provision by powerful providers.