and productivity gains in sub-Saharan African countries. The effect of electrification tends to be larger than that of roads. When supplied simultaneously, these two types of infrastructure reinforce each other, resulting in greater efficiency. Indeed, they are highly complementary in the sense that supplying one significantly raises the marginal effect of the other. This complementarity is robust across the two outcomes we have analyzed so far, and across the two data sources. We next examine heterogeneity in the effects of infrastructure on the type of employment and occupational sectors.

# **5.2 Skilled versus unskilled employment and occupational sectors**

We analyze the separate and joint effects of roads and electricity on skilled and unskilled employment and on different occupational sectors. The results are presented in Table 5 in the Appendix. Access to road and electricity networks increases employment in skilled occupations and decreases employment in unskilled occupations, leading to a structural transformation that consists of a transition from to occupations that entail higher skills.

Expanding the connections to the two networks leads to a significant employment increase in skilled and high-skilled occupations, as evidenced by the findings obtained by both data sources, the DHS sample (columns 4 and 5) and the LSMS sample (Column 9). Being 10 km closer to an electricity grid in locations along a main road increases skilled employment by 10 percentage points (Column 4) in the DHS sample, and high-skilled employment by around 7 percentage points in both the LSMS and DHS samples (columns 5 and 9). Similarly, being 10 km closer to a main road in locations along the electricity grid increases skilled employment by 19 percentage points (Column 4) and high-skilled employment by 10 percentage point in the DHS sample (Column 5), and by 21 percentage points in the LSMS sample (Column 9).

The joint effect of the two types of infrastructure is positive and highly significant, showing that they play complementary roles in the creation of skilled jobs. The marginal impact of getting closer to a main road decreases as distance to the grid increases. Similarly, the marginal impact of getting closer to the grid decreases as distance to a main road increases. Indeed, being 10 km closer to a main road increases the employment gain that results from being 10 km closer to an electricity grid by 4 percentage points for skilled occupations (Column 4) and by 3 percentage points for high-skilled occupations in the DHS sample, and by 20 percentage points for high-skilled occupations in the LSMS sample.

In columns 1, 2, 3, 6, 7, and 8, we show estimates of the effects of roads and electricity on lowskilled employment, including separate effects for farming. Column 1 shows that the probability of selfemployment in the farming sector decreases by 22 percentage points in response to being 10 km closer to a main road in locations along the electricity grid (Column 1). The probability of self-employment in the farming sector decreases to an even greater degree, by 43 percentage points in response to being 10 km closer to an electricity grid in areas along a main road (Column 1). Moreover, being both 10 km closer to a main road and 10 km closer to an electric grid decreases the probability of being self-employed in farming by an additional 13 percentage points.

Columns 2 for the DHS sample and column 6 for the LSMS sample consider employment in the farming sector as the dependent variable.<sup>10</sup> In locations along the grid, being 10 km closer to a main

> 10In column 2, we consider employment in the farming sector as the dependent variable from the DHS. In the LSMS, we

23