We study optimal risk adjustment in imperfectly competitive health insurance markets when high-risk consumers are less likely to switch insurer than low-risk consumers. First, we find that insurers still have an incentive to select even if risk adjustment perfectly corrects for cost differences...

International surveys reveal wide differences between the views held in different countries concerning the causes of wealth or poverty and the extent to which people are responsible for their own fate. At the same time, social ethnographies and experiments by psychologists demonstrate...

I develop a model of ideologies as collectively sustained (yet individually rational) distortions in beliefs concerning the proper scope of governments versus markets. In processing and interpreting signals of the efficacy of public and market provision of education, health insurance, pensions,...

I develop a model of (individually rational) collective reality denial in groups, organizations and markets. Whether participants' tendencies toward wishful thinking reinforce or dampen each other is shown to hinge on a simple and novel mechanism. When an agent can expect to benefit from other's...

This paper analyzes a recent ballot in which two virtually identical popular initiatives, both demanding a decrease in the legal age of retirement in Switzerland, led to differences in approval rates of nearly seven percentage points. Based on this unique natural experiment, the existence of...

This paper exploits a policy-induced natural experiment that occurred in South Australia in the mid-1980s to generate a 'causal' estimate of the effect of schooling on the literacy and numeracy performance of school students in their middle years of secondary school (in Year 9 for most...

There is renewed interest in ways to enhance secondary education, especially among disadvantaged students. This study evaluates the short-term effects of a remedial education programme that provided additional instruction to under-performing high school students in Israel. The programme targeted...

In this paper we test for the theory of deterrence. We exploit the natural experiment provided by the Collective Clemency Bill passed by the Italian Parliament in July 2006. As a consequence of the provisions of the bill, expected punishment to former inmates recommitting a crime can be...

This Paper exploits a unique micro-level data set on primary health care facilities in Uganda to address the question: What motivates religious not-for-profit (RNFP) health care providers? We use two approaches to identify whether an altruistic (religious) effect exists in the data. First,...

In May 1991, 15,000 Ethiopian Jews were brought to Israel in an overnight airlift and sorted in a haphazard and essentially random fashion to absorption centres across the country. This quasi-random assignment produced a natural experiment whereby the initial schooling environment of Ethiopian...