3. For a more thorough review of the poverty literature that includes a discussion of poverty measures, data, and methods, see McKernan, Ratcliffe, and Riegg (2001).
4. Lillard and Willis (1978), Duncan (1984), and to some extent Iceland (1997b) are exceptions.
5. Under the broad view of poverty set forth in the World Bank’s (2001) recent World Development Report “Attacking Poverty,” additional theories, such as theories of empowerment and social capital, would also be required. The World Development Report groups the causes of poverty into three main categories: (1) “lack of income and assets to attain basic necessities;” (2) “sense of voicelessness and powerlessness in the institutions of state and society;” and (3) “vulnerability to adverse shocks, linked to inability to cope with them” (p. 34), but does not provide a theory of poverty.
6. Willis (1986), in his survey of human capital earnings functions, concludes the theory has been “repeatedly confirmed with data from around the world” (p. 598). Also, using the PSID, Duncan (1984) finds “a fair amount of evidence supporting the human capital model” (p. 124).
7. Poverty for this significant minority will be persistent because the culture of poverty is passed from generation to generation.
8. Doeringer and Piore 1971, as cited in Duncan 1984.
9. Entry and exit rates were calculated only for those with no change in family status over the period. Five percent of the sample were excluded from the calculations because of changes in family status.
10. Bane and Ellwood eliminate one-year spells in which income fell by less than one-half of the poverty threshold.
11. While Stevens examines households, Eller and Naifeh focus on families.