(Becker and Tomes, 1979, 1986; Solon, 1992, 1999). These theoretical arguments identify many possible channels through which parental education affects children’s education. For instance, parents affect their children through innate ability, which has an impact on educational attainment, an aspect first formalized by the seminal work of Becker and Tomes (1979). The nutrition and health status of a mother during pregnancy have a huge impact on a child’s initial health endowments and, hence, outcomes in adulthood, including education (Currie, 2009, 2011; Hackman et al., 1983). For instance, a positive relationship between a mother’s education and a child’s birthweight, which is a strong predictor of health outcomes in adulthood, is found throughout the world (Currie and Moretti, 2003). The abilities of parents affect their own income and education outcomes, which determine the quality and quantity of investment in children, thereby affecting the educational attainment of the children (Becker and Tomes, 1979, 1986). First, welleducated parents generally earn higher incomes, which may increase the investment in a child’s education by relaxing resource constraints. Second, higher educational attainment may improve the productivity of parents in child development, thus enhancing activities that may positively affect the educational attainment of children. Finally, parental education directly influences the schooling of children through the choice of school, with an expectation that more able families send their children to more well-endowed schools. In this study, we are not trying to investigate the channels through which intergenerational educational correlations emerge. Our objective is to correlate the educational attainment of parents and children and to present comparisons of trends in intergenerational educational im(mobility) over time.

# **3.1 issues**

Intergenerational mobility studies have been fraught with econometric challenges that have arisen because of unobservable heterogeneity, including the inheritance of genetic endowments such as ability and preference across generations. The partial correlation observed in the data might be mainly driven by the transmission of preference and ability between parents and children. Previous studies attribute the partial, but high correlations between parents’ and children’s educational outcomes to nature and nurture, among other factors (Becker and Tomes, 1986; Haveman and Wolfe, 1995; Black and Devereux, 2011; Checchi et al., 2013). Nature refers to a genetic transmission of the ability of a parent to a child. Able parents have a higher chance of producing to have more able children who can attain higher levels of education without special parental investment. For instance, a child might learn skills through observation without any additional effort from parents (Haveman and Wolfe, 1995; Basu and Getachew, 2015). Nurture pertains to the amount of time and economic investments of parents on a child’s human capital accumulation.

The standard approach in tackling unobserved heterogeneity is to use instrumental variables. The challenge is to identify exogenous variables that affect parental educational attainment, but do not have any effect on children’s educational attainment. However, the instrumental variables used widely in the literature such as family background variables tend to affect children’s outcomes, including our main interest here, education. Some studies use data on adoption (Plug, 2004; Plug and Vijverberg, 2003) and twins (Behrman and Rosenzweig, 2005) to isolate the effect of nature from the effect of nurture. However, these studies are limited to developed countries, where reliable data are available. Other studies compare the effect of nature and nurture on social mobility and find that nurture is relatively more important in explaining parent-child education transmission (Checchi et al., 2013; Haveman and Wolfe, 1995). In the absence of quasi-experimental data and credible instruments, we limit our analysis to the correlation between the educational attainment of parents and children. If factors of nature are time invariant, analyzing changes in intergenerational educational mobility over time is policy relevant without differentiating the effect of nature and nature (Heineck and Riphahn, 2009). Moreover, we are not aware of any analysis of intergenerational educational mobility in our sample countries. Thus, the pattern of partial correlation over time may be of independent interest.

# **3.2 Estimation strategies**

In the literature, the measurement of the degree to which family educational background affects the educational attainment of children has been accomplished in different ways (see Fields and Ok, 2000; Ferreira et al., 2012). Perhaps the most basic measures are _intergenerational correlation_ and _intergenerational elasticity_ . The standard OLS regression model that relates educational attainment transmission from parents to children allows an estimation of these measures: _Eij_ = _α_ + _βEPi_ + _εij,_ (1) 5