efforts are that the members of a given household do not necessarily differ in their sex, age, productive capacity and/or personality profiles; that information is shared symmetrically between cooperative individuals; and that differences in the quantity and quality of land and non-land inputs used by different individuals within or across study households are negligible (Schultz, 2001; Peterman et al., 2011). The extent to which these assumptions are valid in a given subSaharan African setting depends on (i) the complexity of familial structures, including monogamous, polygamous, skipped-generation, and multi-generation households (Peterman et al., 2011), and (ii) the persistence of rights and obligations that affect men and women differently and that are underscored by biological differences, social and religious norms, and customs that jointly dictate the division of labor, land, and proceeds from production units (Saito et al., 1994).

A considerable majority of the studies of the second strand of the literature on the gender gap in sub-Saharan Africa originate from West Africa, specifically from Ghana and Burkina Faso, where it is common for households to have several agricultural plots and for male and female plot managers to coexist in study households. This allows authors to control for unobserved time-invariant household-crop-level heterogeneity in a multivariate regression framework and to estimate agricultural production functions for plots cultivated with the same crop, managed or owned by men and women in the same household. As such, they have evolved to be the most influential studies on gender differences in agricultural productivity in subSaharan Africa, documenting the potential Pareto-inefficient nature of within-household allocation of productive resources. The gender gap is typically identified by the magnitude and statistical significance of the regression coefficient associated with the gender of the plot manager/owner.

The evidence from the second strand indicates that in some contexts, descriptive mean differences in agricultural productivity across plots owned/managed by males vs. females continue to be large and statistically significant in multivariate analyses that control for differences in input use (Saito et al., 1994 for Nigeria; Udry, 1996 for Burkina Faso; Quisumbing et al., 2001 for Ghana; Peterman et al., 2011 for Uganda), while in other contexts, the gender gap ceases to be statistically significant once the researcher controls for differential utilization of productive inputs (Saito et al., 1994 for Kenya; Gilbert et al., 2002 for Malawi; Akresh, 2005 for Burkina Faso; Goldstein and Udry, 2008 for Ghana).<sup>12</sup> A common limitation of these studies is the reliance on data that are at best regionallyrepresentative in terms of population dynamics (with the exception of Akresh, 2005), whereby results have limited external validity beyond the study area, within or across countries. For instance, Akresh (2005) uses nationally-representative data from Burkina Faso, and while he is

> 12 See Peterman et al. (2011) for a succinct review of the main findings of the studies cited here. Only Udry (1996), Quisumbing et al. (2001), Akresh (2005), Goldstein and Udry (2008), and Peterman et al. (2011) conduct withinhousehold analysis.

6