The World Bank Economic Review 17

**Table 8.** Attitudes: Network Spillover and Reinforcing Interaction Effects

||**Condom use**<br>**attitudes**<br>**subindex**|**Sexually**<br>**conservative**<br>**attitudes subindex**|**Sexual abuse**<br>**reporting attitudes**<br>**subindex**|**General**<br>**attitudes index**|
|---|---|---|---|---|
||**(1)**|**(2)**|**(3)**|**(4)**|
|Treatment student|−0.020|0.072|0.024|0.043|
||(0.064)|(0.074)|(0.070)|(0.073)|
|Spillover student|−0.021|0.082|0.021|0.032|
||(0.049)|(0.058)|(0.051)|(0.051)|
|Treatment student * % of friends treated|0.213***|0.114|0.166*|0.236***|
||(0.075)|(0.071)|(0.093)|(0.078)|
|Spillover student * % of friends treated|−0.098|−0.059|−0.003|−0.072|
||(0.170)|(0.143)|(0.131)|(0.147)|
|Number of friends|0.068***|0.006|0.044***|0.052***|
||(0.017)|(0.015)|(0.016)|(0.016)|
|Control for baseline value of dep. var.|Yes|Yes|Yes|Yes|
|_P_-value: treatment * (% of friends)|0.129|0.279|0.270|0.061|
|=spillover * (% of friends)|||||
|Observations|3,856|3,882|3,840|3,891|

_Source_ : Authors’ analysis from student surveys. _Note_ : Dependent variable is an index of related questions. All components of the indices are standardized to mean 0 and standard deviation 1, based on the sample frame at baseline. Standard errors clustered at the school level in parentheses. *** _p <_ 0.01, ** _p <_ 0.05, * _p <_ 0.1. _Condom use attitudes subindex_ : Respondent disagrees with statements (a) “It’s not right to carry a condom because people may think that I planned to have sex”; (b) “If a woman wants to have sex without a condom, the man must not refuse”; (c) “Only women are responsible for unwanted pregnancies”; respondent is (d) confident if requesting that a condom be used; (e) willing to delay sex if condoms are unavailable; respondent thinks (f) he/she will use a condom in his/her next sexual relationship. _Sexually conservative attitude subindex_ : Respondent thinks that (a) it is not right when people of their age have sex with several partners in the same month; (b) people of their age should wait to have sex; respondent’s answer to (c) age at which men and women should start having sex. Respondent is (d) confident he/she will have sex only when emotionally ready. _Sexual abuse reporting attitudes subindex_ : Respondent thinks that when a teenager is suffering from sexual violence (a) he/she must tell his/her family; (b) he/she must tell the authorities; (c) in case of rape, the afflicted individual must seek medical help; respondent disagrees with the idea that in case of rape the person (d) must not tell anyone. _General attitudes index_ : contains all variables used in the other columns of the table.

This provides evidence that the relevant group for a reinforcement effect is the network of friends, as suggested in Sacerdote (2011).

Table 9 presents evidence of reinforcing interaction effects for self-reported sexual behavior: Students with more friends taking the course report significantly lower sexual activity than those with fewer friends taking the course for two out of three indicators.

Column 4 reports results for condom redemption. In contrast to the network interaction results in knowledge and attitudes, the condom redemption results are not significant, although the signs of the coefficients are consistent with tables 8 and 9 in the sense that they point to an improvement the larger the share of friends that is treated. Indeed, treatment students are 8 percentage points more likely to redeem their vouchers than the control group, even if none of their close friends were treated (not statistically significant). The coefficient estimate on the reinforcing interaction suggests a 4.3 percentage point higher condom demand for those with all friends being treated, but again the coefficient is not statistically different from zero.

Column 4 also shows a puzzling result in which spillover students whose entire friend networks were treated are 14 percentage points less likely to redeem their condom vouchers than the control group. Note there is a small number of observations in the spillover group with friendship links to treated students, and the results in all the other indicators do not show a pattern of significant spillovers from classroom to classroom, so the authors do not attach much importance to this coefficient.