We also have information about condom use: the survey investigates condom usage at last intercourse for Swaziland and Zimbabwe, while in Lesotho it elicits information on the last contraceptive method used in the males sample and on condom usage during the last intercourse in the females sample. Looking at the pooled samples of Lesotho and Swaziland almost 33 percent of men report using condoms during their last sexual intercourse compared to 26 percent of women. Condom use is much lower in Lesotho than in the other countries, except for women in Zimbabwe, where the share of respondents using condoms is very low and equal to 8 percent. Another great advantage of the DHS is that it investigates whether the last intercourse occurred with a spouse or with another partner. Hence, we can compare condom use inside and outside the marriage. As expected, the fraction of currently married respondents reporting condom with a spouse is low, ranging from 8 percent in Lesotho to 28 percent in Swaziland for men and from 3.3 percent in Zimbabwe to 22.7 percent in Swaziland for women. A much larger share of people report using condoms outside marriage, with the highest averages recorded in Swaziland.

Turning to the analysis of the independent variables, the share of miners in the sample is equal to 3 percent and the fraction of women with a miner as partner is almost eight times larger. The average age of individuals is 28 years while the average age of the partner in the women sample is much higher and equal to 38 years. Except for Lesotho, where women have the highest educational level of achievement, the average years of education are similar across genders in all the three countries. The share of the urban population is lower in Lesotho compared to Swaziland and Zimbabwe. The analysis uses a set of indicators for durable goods held by the household (television, radio, refrigerator, motorbike, car, bicycle, electricity) as a proxy for wealth. Indeed, the wealth quintiles provided in the DHS can be misleading as a measure of wealth, particularly for African countries: there is generally too little variation in the lowers three quintiles and differences in living standard are difficult to distinguish in those quintiles. Religious affiliations have been regrouped into three categories, Catholic (Roman Catholic Church), Protestant (Evangelical, Methodist, Anglican, Adventist, Pentecostal, other Christian) (the omitted variable in the regressions) and no religion. Finally, in the empirical analysis, we also include two variables capturing individual preferences to spend time away from the household of origin. The first one is a continuous variable indicating the number of nights male respondents have spent away from the household. The second one is a dummy capturing whether the husband lives in the household or not.

# **4. Methodology and potential sources of bias**

The goal of the empirical section is twofold. First, we assess whether individuals working in the mining sector have a higher probability of being HIV positive and if women, with a partner employed in the mines, are at higher risk of being infected with HIV. Second, we test whether miners and miners’ partners are more likely to report risky sexual behaviors compared to individuals with other types of jobs. We run two separate sets of regressions. The first set of equations uses the probability of being HIV positive as the dependent variable. The second one considers sexual behaviors, which are assumed to have an influence on the risk of HIV infection, such as abstinence, extra marital sex and condom usage, as dependent variables. Sexual behavior 10