The Effects of HMOs on Conventional Insurance Premiums: Theory and Evidence

We develop a model of imperfectly competitive insurers that compete with HMOs for consumers who have private information about their health status. We illustrate two conflicting effects of increasing HMO activity on conventional insurance premiums. We term these effects market discipline -- HMO competition may limit the ability of insurers to exercise market power, thus driving prices down -- and market segmentation -- HMOs may skim the healthiest patients, thus driving insurers' costs and prices up. We empirically examine the relative importance of these effects using data from a firm-level survey that provides data on premiums, together with market-level measures of HMO activity. Our results suggest that the market segmentation effect is important, and that increases in HMO activity may increase insurance premiums.

Software Exclusivity and the Scope of Indirect Network Effects in the U.S. Home Video Game Market

This paper investigates the scope of indirect network effects in the home video game industry. We argue that the increasing prevalence of non-exclusive software gives rise to indirect network effects that exist between users of competing and incompatible hardware platforms. This is because software non-exclusivity, like hardware compatibility, allows a software firm to sell to a market broader than a single platform's installed base, leading to a dependence of any particular platform's software on all firms' installed bases. We look for evidence of these market-wide network effects by estimating a model of hardware demand and software supply. Our software supply equation allows the supply of games for a particular platform to depend not only on the installed base of that platform, but also on the installed base of competing platforms. Our results indicate the presence of both a platform-specific network effect and -in recent years- a cross-platform (or generation-wide) network effect. Our finding that the scope of indirect network effects in this industry has widened suggests one reason that this market, which is often cited as a canonical example of one with strong indirect network effects, is no longer dominated by a single platform

Software Exclusivity and the Scope of Indirect Network Effects in the U.S. Home Video Game Market

This paper investigates the scope of indirect network effects in the home video game industry. We argue that the increasing prevalence of non-exclusive software gives rise to indirect network effects that exist between users of competing and incompatible hardware platforms. This is because software non-exclusivity, like hardware compatibility, allows a software firm to sell to a market broader than a single platform's installed base, leading to a dependence of any particular platform's software on all firms' installed bases. We look for evidence of these market-wide network effects by estimating a model of hardware demand and software supply. Our software supply equation allows the supply of games for a particular platform to depend not only on the installed base of that platform, but also on the installed base of competing platforms. Our results indicate the presence of both a platform-specific network effect and -in recent years- a cross-platform (or generation-wide) network effect. Our finding that the scope of indirect network effects in this industry has widened suggests one reason that this market, which is often cited as a canonical example of one with strong indirect network effects, is no longer dominated by a single platform