However, when we examine the effects of HTC on those who tested HIV-positive at baseline, the story is starkly different (Panel C). Among the 73 HIV-positive individuals in our sample, the follow-up prevalence of HSV-2 is 23.1 percentage points higher in the HTC group than the control group mean of 25.5% -- statistically significant at the 10% level.<sup>22</sup> Self-reports suggest changes in subjective beliefs as well: those in the HTC arm who receive HIV-positive tests assign a higher average probability to being HIV-positive at follow-up.<sup>23</sup> The self-reported outcomes on sexual behavior suggest some increase in sexual activity and the number of partners during the past 12 months but none of these variables is statistically significant. We do not find any significant effects on test scores.<sup>24</sup> As described earlier, our naïve estimator of HTC impacts by baseline HIV status is biased by the presence of HIV-seroconverters among the counterfactual group at follow-up. To assess whether the HTC effect on HSV-2 prevalence among the HIV-positive subgroup is robust to this issue, we conduct a bounding exercise, which was summarized in the previous section and formally outlined in Appendix C.<sup>25</sup> While the lower and upper bounds for the true ITT estimate can be calculated analytically, in order to provide standard errors on the bounds we calculate them empirically. We do this by repeatedly and randomly excluding the expected number of HIV-seroconverters from our analysis and recalculating the HTC effect on HSV-2. The baseline HIV prevalence in the HTC group is 3.96% while the follow-up HIV prevalence in the control group is 5.03%. Neither of these figures is affected by HTC as they both reflect prevalence rates in each study arm prior to HTC. The difference between these two figures, which is equal to the

> 22 The adjusted estimate is very similar at 24.6 percentage points and significant at the 1% level.

> 23 While the average HTC effect on beliefs of HIV infection is strong and statistically significant, 43% of those who received HIV-positive test results reported _no_ (zero) chance of being infected with HIV at the follow-up survey. This finding is unlikely to be due to the testing procedures. As detailed in Appendix A, those who tested positive with one rapid test received a second independent test using a different test kit. On the very unlikely event that the two test results were discordant, a third test was administered to break the tie. It is consistent with two other studies from Malawi, both of which find that approximately 40% of individuals who received HIV-positive test results through a VCT intervention reported _no_ likelihood of being infected in a follow-up survey (Thornton 2012; Delavande and Kohler 2012).

> 24 The reader should note the limited statistical power of the impact analysis among this subgroup due to its small size in our sample. We have a total of 73 HIV-positive individuals in our analysis, which is similar in size to Thornton (2012) who uses a sample of 79 HIV-positive individuals, and Delavande and Kohler (2012) who use a sample of 97 HIV-positive individuals. Gong (2013), using data on an older sample of people who were seeking HIV-related services, analyzes a sample of 465 HIV-positive individuals.

> 25 We do not present the results of the bounding exercise for the HIV-negative group because the small number of HIV-seroconverters forms a negligible share of the sample of 1,607 HIV-negative individuals and, hence, does not bias our estimates in any meaningful way.

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