Community Rating, Cross Subsidies and Underinsurance: Why so many Households in Japan do not Purchase Earthquake Insurance

  • Michio Naoi
  • Miki Seko
  • Kazuto Sumita


A theoretical framework and empirical evidence are presented to show the connection between community uniform rating and cross-subsidies in earthquake insurance policy in Japan. Cross-subsidies are defined as the difference between a fair actuarial premium and the community uniform rate. The estimation result shows that the uniform community rating may unintentionally cross-subsidize inhabitants in high risk areas at the expense of inhabitants in low risk areas. Our simulation results indicate that replacing the current community rating with the fair actuarial premium would increase the overall subscription rate for earthquake insurance by about 3.7 percentage point, and that the increase is particularly prominent in relatively less risky areas. We propose modifying the Japanese earthquake insurance system by adopting a more refined risk rating system that more closely reflects regional differences in earthquake risk.


Earthquake insurance Cross-subsidization Risk Japan 



We are grateful to the National Research Institute for Earth Science and Disaster Prevention (NIED) for generously providing us with the data on earthquake hazard information. We also thank K. W. Chau, Dwight M. Jaffee, an anonymous referee and participants at the Asia-Pacific Real Estate Research Symposium (APRES) for their helpful comments and suggestions. The first author (Michio Naoi) acknowledges a Grant-in-Aid (#19730183) for Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology. Also, the second and third authors (Miki Seko and Kazuto Sumita) acknowledge a Grant-in-Aid (#19530157) for Scientific Research (C) from the Ministry of Education Culture, Sports, Science and Technology.


  1. Arrow, K. (1963). Uncertainty and the welfare economics of medical care. American Economic Review, 53(5), 941–973.Google Scholar
  2. Browne, M. J., & Hoyt, R. E. (2000). The demand for flood insurance: empirical evidence. Journal of Risk and Uncertainty, 20(3), 291–306.CrossRefGoogle Scholar
  3. Ehrlich, I., & Becker, G. S. (1972). Market insurance, self-insurance, and self-protection. Journal of Political Economy, 80(4), 623–648.CrossRefGoogle Scholar
  4. Jaffee D. M., & Russel T. (2000). Behavioral models of insurance: The case of the California Earthquake Authority. Paper presented at the NBER Insurance Project Workshop.Google Scholar
  5. Kunreuther, H. (1984). Causes of underinsurance against natural disasters. Geneva Papers on Risk and Insurance, 9(31), 206–220.Google Scholar
  6. Laffont, J. J. (1989). The economics of uncertainty and information. Cambridge: MIT.Google Scholar
  7. Leung, C. K. Y. (2001). Productivity growth, increasing income inequality and social insurance: the case of China? Journal of Economic Behavior and Organization, 46(6), 395–408.CrossRefGoogle Scholar
  8. Leung, C. K. Y., Tang, S. H. K., & Groenewold, N. (2006). Growth volatility and technical progress: a simple rent-seeking model. Journal of Economics (Zeitschrift für Nationalökonomie), 88(2), 159–178.CrossRefGoogle Scholar
  9. Naoi, M., Sumita, K., & Seko, M. (2007). Earthquakes and the quality of life in Japan. Journal of Property Research, 24(4), 313–334.CrossRefGoogle Scholar
  10. Naoi, M., Seko, M., & Sumita, K. (2009). Earthquake risk and housing prices in Japan: Evidence before and after massive earthquakes. Regional Science and Urban Economics, 39(6), 658–669.CrossRefGoogle Scholar
  11. Pauly, M. V. (1970). The welfare economics of community rating. Journal of Risk and Insurance, 37(2), 407–418.CrossRefGoogle Scholar
  12. Picard, P. (2008). Natural disaster insurance and the equity-efficiency trade-off. Journal of Risk and Insurance, 75(1), 17–38.CrossRefGoogle Scholar
  13. Pupp, R. L. (1981). Community rating and cross-subsidization in health insurance. Journal of Risk and Insurance, 48(4), 610–627.CrossRefGoogle Scholar
  14. Rothschild, M., & Stiglitz, J. (1976). Equilibrium in competitive insurance markets: an essay on the economics of imperfect information. Quarterly Journal of Economics, 90(4), 629–649.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Faculty of EconomicsKeio UniversityTokyoJapan
  2. 2.Faculty of EconomicsKeio UniversityTokyoJapan
  3. 3.Department of EconomicsKanazawa Seiryo UniversityIshikawaJapan

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