Selection in car insurance when claims are heterogeneous
利用意大利车险数据，研究发现仅凭责任险理赔作为风险度量来检验信息不对称，会因附加险种不同或理赔指标不当而得出矛盾结果，表明选择效应可能沿理赔概率未捕捉的风险维度运作。
Abstract Econometric studies of insurance markets have analyzed the Positive Correlation Property to test for the presence of asymmetric information. Car‐insurance studies frequently compare policies purchasing Mandatory Third‐Party Liability alone with policies that purchase additional coverage and use the presence of a liability claim as a measure of risk. Using data from the Italian market, we show that this approach can yield conflicting results from the same dataset. First, different types of additional coverage can yield different results; second, the presence of a claim is a poor or even misleading indicator of the cost to the insurance company. A test using an unused observable is similarly problematic. Our findings highlight that selection may operate along dimensions of risk not captured by claim probabilities, complicating the interpretation of standard empirical tests and the distinction between adverse and advantageous selection.