The variance in the logarithms of per capita GDP in purchasing power-parity prices increased in the world form 1960 to 1968 and decreased since the mid 170s. In the later period the convergence in intercountry incomes more than offset any increase in within country inequality. Approximately...

Recall bias is a pervasive problem in the analysis of retrospective data (Shyrock et al., 1973; Ewbank, 1981). The problem is a recurrent concernin the litterature on the determinants of breastfeeding duration, its trend over time, and the effect of breastfeeding on infant mortality.