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Unformatted text preview: f the incentive (panel B). These
figures illustrate the large impact of receiving an incentive on attendance. Error bars are also
presented showing precisely estimated effects. Figure 4, panel A, presents the impact of distance
of residence from the nearest results center on attendance, estimated by a nonparametric, locally
weighted regression (Jianqing Fan 1992). Distance had a strong negative effect on attendance,
especially pronounced among those living farther than 1.5 kilometers from the results center.
To measure the demand for learning HIV results in a regression framework, I estimate:
(1) GotResultsij 5 a 1 b1 Anyij 1 b2 Amtij 1 b3 Amt2 1 b4 Distij 1 b5 Dist2 1 X9 m 1 eij .
ij Attendance at the VCT center is indicated by GotResults 5 1 for person i in village j. Any indicates if the respondent received any nonzero voucher and Amt is the dollar amount of the incentive. Including the binary indicator as well as the squared term allows for nonlinear effects of
the incentive. Dist is the number of kilometers from the randomly placed VCT center assigned
to person i. A vector of controls, X, includes covariates of gender, age, age-squared, HIV status,
and district dummies, as well as a control for a simulated average distance in each VCT zone.
Because the locations of the centers were chosen randomly, as opposed to randomly assigning
the distance needed to travel, I draw 1,000 simulated random locations in each VCT zone and
calculate the average distance of each tested respondent from each of the 1,000 simulated locations. I average this distance for each respondent and take the mean across all respondents living
in each zone.9 Standard errors are clustered by village, for 119 villages.10 Although the dependent
variable is binary, the linear specifications do not differ greatly from estimations from probits;
both results are presented (see also Joshua D. Angrist 2001).
Seeking HIV results was highly responsive to incentives. The average VCT center attendance
of those receiving any positive-valued voucher is more than twice that of those receiving no
possible that individuals overestimate the potential psychological effects of receiving an HIV diagnosis (Tim Wilson
and Dan Gilbert 2003...
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