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Spell incidence, spell duration and the measurement of unemployment


The proportion of the population out of work is an unsatisfactory measure of unemployment because it is indifferent to the way in which a given amount of unemployment time is distributed across the population. This paper offers a new way of measuring unemployment which takes account of both the frequency and duration of unemployment spells. The proposed unemployment index may be interpreted as the ‘welfare equivalent’ period of unemployment, and decomposes into the product of three components: a spell incidence factor, a duration factor, and the average unemployment rate.

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  1. 1.

    Aczel, J.: Lectures on Functional equations and Their Applications. Academic, New York (1966)

    Google Scholar 

  2. 2.

    Akerlof, G.A., Main, B.G.M.: Unemployment spells and unemployment experience. Am. Econ. Rev. 70, 885–893 (1980)

    Google Scholar 

  3. 3.

    Akerlof, G.A., Main, B.G.M.: An experience-weighted measure of employment and unemployment duration. Am. Econ. Rev. 71, 1003–1011 (1981)

    Google Scholar 

  4. 4.

    Atkinson, A.B.: On the measurement of inequality. J. Econ. Theory 2, 244–263 (1970)

    Article  Google Scholar 

  5. 5.

    Baker, M.: Unemployment duration: compositional effects and cyclical variability. Am. Econ. Rev. 82, 313–321 (1992)

    Google Scholar 

  6. 6.

    Bane, M.J., Ellwood, D.T.: Slipping into and out of poverty: the dynamics of spells. J. Hum. Resour. 21, 1–23 (1986)

    Article  Google Scholar 

  7. 7.

    Bowers, N.: Probing the issues of unemployment duration. Mon. Labor Rev. 103, 23–32 (1980)

    Google Scholar 

  8. 8.

    Carlson, J.A., Horrigan, M.W.: Measures of unemployment duration as guides to research and policy, comment. Am. Econ. Rev. 73, 1143–1150 (1983)

    Google Scholar 

  9. 9.

    Chamberlain, G.: Heterogeneity, omitted variable bias, and duration dependence. In: Heckman, J.J., Singer, B. (eds.) Longitudinal Analysis of Labor Market Data, pp. 3–38. Cambridge University Press, Cambridge (1985)

    Chapter  Google Scholar 

  10. 10.

    Clark, K.B., Summers, L.H.: Labor market dynamics and unemployment: a reconsideration. Brookings Pap. Econ. Act. 1, 13–72 (1979)

    Article  Google Scholar 

  11. 11.

    Clark, K.B., Summers L.H.: Unemployment reconsidered. Harv. Bus. Rev. 58, 171–179 (1980)

    Google Scholar 

  12. 12.

    Cowell, F.A., Kuga, K.: Additivity and the entropy concept: an axiomatic approach to inequality measurement. J. Econ. Theory 25, 131–143 (1981)

    Article  Google Scholar 

  13. 13.

    Disney, R.: Recurrent spells and the concentration of unemployment in Great Britain. Econ. J. 89, 109–119 (1979)

    Article  Google Scholar 

  14. 14.

    Flaim, P.O., Hogue, C.R.: Measuring labor force flows: a special conference examines the problems. Mon. Labor Rev. 108, 7–17 (1985)

    Google Scholar 

  15. 15.

    Hall, R.E.: Turnover in the labor force. Brookings Pap. Econ. Act. 3, 709–756 (1972)

    Article  Google Scholar 

  16. 16.

    Heckman, J.J., Singer, B.: Econometric duration analysis. J. Econom. 24, 63–132 (1984)

    Article  Google Scholar 

  17. 17.

    Heckman, J.J., Singer, B.: A method for minimizing the impact of distributional assumptions in econometric models for duration data. Econometrica 52, 271–320 (1984)

    Article  Google Scholar 

  18. 18.

    Heckman, J.J., Singer, B.: Longitudinal Analysis of Labor Market Data. Cambridge University Press, Cambridge (1985)

    Book  Google Scholar 

  19. 19.

    Horrigan, M.W.: Time spent unemployed: a new look at data from the CPS. Mon. Labor Rev. 110, 3–15 (1987)

    Google Scholar 

  20. 20.

    Kaitz, H.B.: Analyzing the length of spells of unemployment. Mon. Labor Rev. 93, 11–20 (1970)

    Google Scholar 

  21. 21.

    Kiefer, N.M.: Economic duration data and hazard functions. J. Econ. Lit. 26, 646–679 (1988)

    Google Scholar 

  22. 22.

    Kiefer, N.M., Lundberg, S.J., Neumann, G.R.: How long is a spell of unemployment? Illusions and biases in the use of CPS data. J. Bus. Econ. Stat. 3, 118–128 (1985)

    Article  Google Scholar 

  23. 23.

    Lancaster, T.: Econometric methods for the duration of unemployment. Econometrica 47, 939–956 (1979)

    Article  Google Scholar 

  24. 24.

    Lancaster, T.: The econometric analysis of transition data. Cambridge University Press, Cambridge (1990)

    Google Scholar 

  25. 25.

    Layard, R.: Measuring the duration of unemployment: a note. Scott. J. Polit. Econ. 28, 273–277 (1981)

    Article  Google Scholar 

  26. 26.

    Main, B.G.M.: The length of employment and unemployment in Great Britain. Scott. J. Polit. Econ. 28, 146–164 (1981)

    Article  Google Scholar 

  27. 27.

    Morgenstern, R.D., Barrett, N.S.: The retrospective bias in unemployment reporting by sex, race and age. J. Am. Stat. Assoc. 69, 355–357 (1974)

    Article  Google Scholar 

  28. 28.

    Nickell, S.J.: Estimating the probability of leaving unemployment. Econometrica 47, 1249–1266 (1979)

    Article  Google Scholar 

  29. 29.

    Perry, G.L.: Unemployment flows in the U.S. labor market. Brookings Pap. Econ. Act. 3, 245–278 (1972)

    Article  Google Scholar 

  30. 30.

    Ruggles, P.: Drawing the Line: Alternative Poverty Measures and Their Implications for Public Policy. Urban Institute, Washington, DC (1990)

    Google Scholar 

  31. 31.

    Salant, S.W.: Search theory and duration data: a theory of sorts. Q. J. Econ. 91, 39–57 (1977)

    Article  Google Scholar 

  32. 32.

    Sen, A.K.: Poverty: an ordinal approach to measurement. Econometrica 44, 219–231 (1976)

    Article  Google Scholar 

  33. 33.

    Sen, A.K.: Issues in the measurement of poverty. Scand. J. Econ. 81, 285–307 (1979)

    Article  Google Scholar 

  34. 34.

    Shorrocks, A.F.: The class of additively decomposable inequality measures. Econometrica 48, 613–625 (1980)

    Article  Google Scholar 

  35. 35.

    Shorrocks, A.F.: Inequality decomposition by population subgroups. Econometrica 52, 1369–1385 (1984)

    Article  Google Scholar 

  36. 36.

    Sider, H.: Unemployment duration and incidence. Am. Econ. Rev. 75, 461–472 (1985)

    Google Scholar 

  37. 37.

    U.S. Department of Labor, Bureau of Labor Statistics: handbook of labor statistics August, 1989

  38. 38.

    U.S. Department of Labor, Bureau of Labor Statistics: employment and earnings January, 1991

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Correspondence to Anthony Shorrocks.

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Shorrocks, A. Spell incidence, spell duration and the measurement of unemployment. J Econ Inequal 7, 295–310 (2009).

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  • Unemployment
  • Duration
  • Incidence
  • Indices