Abstract
Sociologists and economists reach quite different conclusions about how intergenerational mobility in the UK compares for those growing up in the 1970s and 1980s. Persistence in social class is found to be unchanged while family income is found to be more closely related to sons’ earnings for those born in 1970 compared to those born in the 1958. We investigate the reasons for the contrast and find that they are not due to methodological differences or data quality. Rather, they are explained by the increased importance of differences in income within social class for sons’ earnings in the second cohort. When economists measure intergenerational mobility their ideal is to see how permanent income is transmitted across generations. Our investigations show that the importance of within-social class differences in income mean that a single measure of income is a better predictor of permanent income status than fathers’ social class. We would not, therefore, expect the results for changes in intergenerational mobility based on income and social class to necessarily coincide.