Southern Africa Labour and Development Research Unit
What do people actually learn from public
health education campaigns? Incorrect inferences
about male circumcision and female HIV infection
risk in a cluster randomized trial in Malawi
by
Brendan Maughan-Brown, Susan Godlonton,
Rebecca L. Thornton and Atheendar S Venkataramani
Working Paper Series
Number 104
About the Author(s) and Acknowledgments
Brendan Maughan-Brown, Southern Africa Labour and Development Research Unit,
University of Cape Town; Susan Godlonton, Ford School of Public Policy, University of Michigan; Rebecca
L. Thornton, Department of Economics, University of Michigan; Atheendar S Venkataramani, Department
of Medicine, Massachusetts General Hospital
We would like to thank Martin Abel, Nicola Branson, Arden Finn, David Maughan-Brown, Rebecca
Maughan-Brown and Elizabeth Gummerson for helpful comments and suggestions. Brendan MaughanBrown is grateful for funding from the National Research Foundation (NRF) Research Chair in Poverty
and Inequality Research for his Postdoctoral Research Fellowship. Atheendar S. Venkataramani is grateful
to the Massachusetts General Hospital Global Primary Care Program for travel and research support.
Opinions expressed and conclusions arrived at, are those of the authors and are not necessarily to be
attributed to the NRF. We acknowledge the extensive contributions of the field team including James
Amani, Sheena Kayira, Collins Kwizombe, Denise Matthijsse, Ernest Mlenga, and Christopher Nyirenda. We
also thank assistance from Kondwani Chidziwisano, Jessica Kraft, Erica Marks, Julie Moran, Jason Stanley,
and Kondwani Tomoko.
Sources of Funding: Funding for this study was provided by Michigan Center for Demography of Aging
(MiCDA), OVPR and Rackham at the University of Michigan as well as the Institute for Research on Women
and Gender. Godlonton and Thornton gratefully acknowledge use of the services and facilities of the
Population Studies Center at the University of Michigan, funded by NICHD Center Grant R24 HD041028.
The funders had no role in the collection, analysis, and interpretation of data, manuscript preparation, and
in the decision to submit the article for publication.
Recommended citation
Maughan-Brown, B., Godlonton, S., Thornton, R., Venkataramani, A. (2013). What do people actually learn
from public health education campaigns? Incorrect inferences about male circumcision and female HIV
infection risk in a cluster randomized trial in Malawi. A Southern Africa Labour and Development Research
Unit Working Paper Number 104. Cape Town: SALDRU, University of Cape Town
ISBN: 978-1-920517-45-8
© Southern Africa Labour and Development Research Unit, UCT, 2013
Working Papers can be downloaded in Adobe Acrobat format from www.saldru.uct.ac.za.
Printed copies of Working Papers are available for R15.00 each plus vat and postage charges.
Orders may be directed to:
The Administrative Officer, SALDRU, University of Cape Town, Private Bag, Rondebosch, 7701,
Tel: (021) 650 5696, Fax: (021) 650 5697, Email: [email protected]
What do people actually learn from public health education
campaigns? Incorrect inferences about male circumcision
and female HIV infection risk in a cluster randomized trial in
Malawi
Brendan Maughan-Brown, Susan Godlonton, Rebecca L. Thornton and Atheendar S Venkataramani
SALDRU Working Paper Number 104
University of Cape Town
August 2013
Abstract
Objective: To examine whether individuals who learn that voluntary medical male
circumcision (VMMC) partially reduces female-to-male HIV transmission erroneously infer a
reduction in male-to-female HIV transmission risk.
Design: Cluster randomised controlled trial.
Methods: In 2008, information that VMMC reduces female-to-male HIV transmission risk
was randomly disseminated to men in rural Malawi, with follow-up in 2009 (n=917). Data
was collected on perceived male and female HIV-transmission risks. We assessed whether
beliefs about male circumcision and female HIV-risk varied by receipt of VMMC information
and by whether or not individuals believed that VMMC partially protects men from HIVinfection.
Results: Men informed about VMMC were more likely to believe that sex with a
circumcised male would confer lower transmission risk for women vis-à-vis sex with an
uncircumcised male (38% versus 50%, p <0.01). Multivariate regression analyses showed
that incorrect inferences were most likely to be made by those who believed that
circumcised men were partially protected from contracting HIV. Consistent with this,
instrumental variable analyses indicated that those individuals who received information
about VMMC, and consequently believed it, were 82 percentage points more likely to
believe that male circumcision also protects women (p<0.01). The inferred reduction in
direct HIV infection risk for women due to male circumcision was approximately 50%.
Conclusions: Our results suggest the need for VMMC campaigns to make explicit that male
circumcision does not directly protect women from HIV-infection. It is also important to
assess whether incorrect inferences lead to updated self-perceived HIV-risk and the
adoption of riskier sexual behaviours.
Keywords: Male circumcision, female HIV risk, risk compensation, Southern Africa, HIV/AIDS,
prevention, information campaigns
Introduction
Randomised clinical trials (RCTs) have shown that medical male circumcision
substantially reduces the risk of female-to-male HIV transmission risk [1-4], but have found
no significant relationship with male-to-female HIV transmission risk [5]. In response to
these findings, many countries are rolling out large-scale voluntary medical male
circumcision (VMMC) campaigns in order to reduce heterosexual male infections [6]. In
order to create demand for VMMC, these countries have started disseminating information
that male circumcision offers men partial protection against HIV-infection [7] (see Figure A1,
Appendix, for an example).
Several concerns arise with such information campaigns. With respect to VMMC,
men may respond to information regarding its protective benefits by updating their beliefs
about their own HIV-risk and consequently adopt riskier sexual behaviours.8-10 While a
recent literature using experimental methods has found no evidence of risk compensation
after a medical circumcision, it is unclear whether these null results generalise to other
settings [11-14].
Another important, but not was well studied, concern is that individuals will
erroneously infer that a reduction in the risk of female-to-male transmission of HIV due to
VMMC also implies a lower risk of male-to-female transmission. Qualitative work has shown
that a significant number of women may hold these incorrect beliefs [15,16]. These small
sample findings are supported by evidence from a South African opinion poll showing that
approximately a fifth of men and women believed that VMMC reduced the risk of HIV
transmission from men to women [17]. Such incorrect inferences may be detrimental to HIV
prevention efforts if they lead to updated self-perceived HIV-risk that ultimately encourage
adoption of riskier sexual behaviours.
This paper uses data from Malawi to examine whether men infer a lower risk of
male-to-female transmission of HIV as a result of VMMC when randomly provided
information about the protective benefits that accrue to men. Exploring whether incorrect
inferences arise is important not only in the context of VMMC based prevention efforts, but
also to better understand how and what individuals learn from public health messages, and
any consequent threats to their efficacy, more generally.
Methods
Data
We used pre-existing data from a randomised trial of a behavioural intervention
conducted among Malawian men between October 2008 and November 2009 [13]. The trial
was originally conceived to examine whether information about the protective benefits of
male circumcision changed safe sexual practices among uncircumcised and circumcised
men. Face-to-face baseline surveys were fielded between October and November 2008 in
the Zomba district, located in the southern region of the country. Follow-up interviews were
conducted approximately one year after the intervention with approximately 78% of the
initial sample.
A two-stage sampling strategy was used to select respondents. First, 70 villages were
randomly selected, stratified by the distance from the nearest mosque. A full household
2
enumeration was conducted within each of these villages. Second, men aged 25 to 40 were
randomly selected from the census of 2,567 men in the sample villages, stratified by
religious affiliation (Christian or Muslim) in order to balance the sample across baseline
circumcision status (given the high correlation between religion and circumcision in
Malawi). Up to 20 men of each religious faith were selected from each village. A total
desired sample size of 1380 individuals split across treatment and control was computed to
detect a standardized effect size of 0.25 on condom use with 90% confidence and 90%
power.
At baseline, half the villages (35) were randomly assigned (using a random number
generator) to the information treatment [13]. After completing the baseline interview,
interviewers discussed a standardised information sheet (Figure 1) that explained the three
randomised controlled trials that were conducted in Uganda, South Africa, and Kenya.
Information was provided on the medical reasons why male circumcision is partially
protective for men. Information on male circumcision and female HIV-infection risk was not
explicitly provided. The lack of explicit information about transmission risk to women
mirrors the content of most VMMC information campaigns [7] (see Figure A1, Appendix, for
an example). The University of Michigan Institutional Review Board and the National Health
Sciences Research Committee in the Ministry of Health of Malawi granted ethical approval
for the study.
To measure perceived HIV risk, participants were asked at baseline: “If 100
circumcised men slept with an HIV positive women last night, how many of them would
acquire HIV?” They were also asked a similar question with reference to uncircumcised
men: “If 100 uncircumcised men slept with an HIV positive women last night, how many of
them would acquire HIV?”
These questions were repeated verbatim at follow-up. At that time, respondents
were also asked two questions assessing the relationship between male circumcision and
female risk of HIV infection. The first question was “If 100 women each sleep with a
circumcised man who is HIV positive last night, how many of them do you think would get
HIV?” The second was “If 100 women each sleep with an uncircumcised man who is HIV
positive last night, how many of them do you think would get HIV?”
For each survey wave, we created a binary variable (=1) denoting respondents who
reported a lower risk for circumcised men compared to uncircumcised men. Similarly, we
created a binary variable (=1) for individuals who believed that women who have
unprotected sex with an HIV-positive circumcised man would be at lower risk than when the
man is uncircumcised. In addition, we created a continuous variable defined as the
difference in perceived risk (i.e. number out of 100) for women who have unprotected sex
with an HIV-positive circumcised man compared to women who have unprotected sex with
an HIV-positive uncircumcised man. This variable provides a measure of the degree to which
respondents believed that male circumcision directly lowers a woman’s risk of HIV infection.
Analysis
We first analysed differences in baseline socioeconomic and demographic
characteristics in the VMMC information treatment and controls groups to evaluate the
success of randomisation. We then compared the measures of beliefs about the protective
benefits of circumcision accruing to men and women across the two groups. This analysis
recovers the average impact of randomised exposure to treatment regardless of whether
3
the respondents believed the messages or not (i.e. intent-to-treat estimate).
We next assessed the proportion of men at follow-up that believed that VMMC
partially protected men against HIV who also believed that VMMC lowered a woman’s risk
of HIV infection. This analysis is salient given that the latter (correct) belief is the end goal of
campaigns to create awareness and demand for VMMC. Additionally, to obtain an initial
assessment of the degree to which these particular men believed that VMMC protects
women, we computed the average of the difference in perceived HIV infection risk for
women with a circumcised versus uncircumcised male partner.
We then estimated three sets of multivariate models. In the first, we regressed our
two dependent variables of interest against a dummy indicator (= 1) for assignment to the
information treatment about VMMC, controlling for a number of baseline socioeconomic
characteristics which we describe below. This set of models effectively serves as a
multivariate generalisation of the means analysis described above and serves as a
benchmark for subsequent analyses.
In the second set of models, we added a binary indicator of whether the individual
reported, in 2009, that circumcision is protective for men. The aim of these models were to
assess the extent to which the effect of the information treatment was mitigated after
controlling for beliefs about risk for men; that is, to assess whether incorrect inferences
about risk for women driven by treatment worked through forming correct beliefs about
risk for men.
Our third set of models uses an instrumental variables (IV) strategy to examine the
likelihood of forming incorrect beliefs as a result of internalising VMMC education
messages, as well as the degree to which this erroneous belief was held. Specifically, we
used the randomised treatment indicator as an instrument for believing that VMMC
partially protected men from HIV, which serves as our primary explanatory of interest. This
analysis provides the Local Average Treatment Effect (LATE) estimate of the effect of the
information treatment on those who were actually affected by its message (i.e. treatment
on treated estimate) [18]. For example, in models examining whether or not an individual
believes that female HIV risk is lower with sex with a circumcised man, the coefficient on the
main independent variable can be interpreted as the effect on the likelihood of inferring a
protective benefit for women among those men who on the margin were induced, as a
result of random assignment to information, to move from not believing that VMMC was
protective for men to holding this belief. This LATE estimate is policy relevant for the same
reason as stated above: VMMC campaigns seek to increase demand by shifting beliefs about
circumcision’s HIV risk protective benefits.
The validity of the IV approach relies on (1) the instrument being correlated with the
explanatory variable of interest but (2) not with any other factor that may influence the
outcome. As in Godlonton et al. (2012), we show below that random assignment to
treatment is strongly correlated with beliefs about the protective benefits of VMMC for
men.13 As for the second condition, we argue that the information treatment is likely
uncorrelated with any other determinants of the dependent variable; it is difficult to
imagine how a simple, discrete message about VMMC and male HIV risk could affect beliefs
about risks to women other than through the internalisation about beliefs about male risks.
For our multivariate analyses, the following control variables from the baseline
(2008) survey were included in each of the models: circumcision status, age, years of
education, literacy in Chichewa (the most commonly spoken local language), number of
4
household assets, logged monthly household income (with incomes or zero replaced with 1
Kwacha (n=13)), the number of HIV-related radio messages heard the past 30 days, and an
indicator of whether the respondent believed that HIV is transmitted via mosquitoes or
kissing. Also of note, Ordinary Least Squares (OLS) regression models were also used for all
models with binary dependent variables, for ease of interpretation. Using OLS for binary
dependent variables is a valid statistical method [19]. Results are robust to logit, probit or
odds ratio models. All standard errors were corrected for heteroskedasticity and for
clustering at the village level (the unit of randomisation).
Results
The baseline (2008) sample consisted of 1,228 male respondents (treatment group:
n=609; control group: n=619). Approximately 78% (n=953; treatment group: n=484(79%);
control group: n=468(76%)) were re-interviewed in 2009. Reasons for loss to follow-up
included participants moving to other regions, being unreachable at the address or
telephone number provided and refusal participate. Previous analysis found that attrition in
this sample was not significantly associated with treatment status, circumcision status, age,
education, marital status, or perceptions about male circumcision and HIV risk [13]. The
sample used in the current analysis consisted of 917 men who were interviewed in both
waves and for whom we had complete data for all relevant dependent and independent
variables. Complete data was not available for 18 men in the treatment group and 18 men
in the control group.
Table 1 presents summary statistics of baseline (2008) characteristics and beliefs
about male circumcision and HIV risk (2008 & 2009) by treatment (n=466) and control
groups (n=451). The results indicate that the treatment and control groups had
substantively similar demographic characteristics, access to information, and knowledge
about HIV (see Table A1, Appendix, which demonstrates statistical equivalence across an
additional set of baseline demographic characteristics). Overall, the sample comprised
relatively poor, married men with low levels of education (the average respondent had
completed only 1 year of high school). The majority were farmers whose access to the
media consisted of listening to the radio. Understanding about HIV transmission was poor:
almost two thirds of individuals in the treatment and control groups reported the belief that
HIV can be transmitted by mosquitoes or through kissing.
Consistent with the broader literature [22-22], respondents vastly overestimated the
probability of HIV transmission. At baseline, participants in the treatment and control group
believed, on average, that around 90 out of 100 (90%) uncircumcised men would get HIV if
they had unprotected sex with an HIV positive woman and that around 81% of circumcised
men would get HIV if they had unprotected sex with an HIV positive woman. On average,
participants in 2008 believed that circumcised men experienced a 10 percentage point
reduction (p<0.001) in the chance of contracting HIV after a single encounter with an
infected partner vis-à-vis uncircumcised men. At follow-up, the average participant reported
a significantly lower perceived risk for circumcised men compared to their baseline beliefs in
both the treatment (-17 percentage points, p<0.01) and control group (-11 percentage
points, p<0.01). Overall, the majority of individuals in the treatment group (56%) and a
significant proportion of the control group (45%) reported a decrease in perceived HIV risk
5
for circumcised men between surveys (results not shown).
With regard to perceived female HIV risk at follow-up in 2009, participants reported
that on average around 90 out of a hundred women would get HIV if they had unprotected
sex with an uncircumcised man living with HIV. Significant proportions of men in the
treatment (50%) and control group (38%) reported the belief that the HIV risk for women is
lower when her sexual partner is a circumcised man compared to an uncircumcised man.
Perceived female HIV risk in the scenario involving a circumcised man was, on average, 17
percentage points lower (p<0.01) in the treatment group and 11 percentage points lower
(p<0.01) in the control group. The difference across treatment and control in the differential
perceived risk to women across uncircumcised and circumcised individuals was 6% (p<0.01).
The lower panel in Table 1 presents perceived HIV risk for women with respect to
VMMC among those that believed (in 2009) that male circumcision partially protects men
against HIV infection. The vast majority of participants in both the treatment (73%) and
control group (70%) who believed that VMMC protects men also believed that VMMC
protects women. The average participant in the treatment group who believed that VMMC
protects men reported the belief that VMMC protects women by 26 percentage points. Put
differently, they believed that male circumcision led to roughly a 30% reduction in the
female risk of contracting HIV (26 percentage points divided by the sample risk of
contracting HIV with an uncircumcised partner).
Table 2 presents the results from the multivariate regression models. The results in
the first column show that random assignment to the information treatment was associated
with a 10 percentage point increase in the likelihood of believing that male circumcision
lowers a woman’s risk of HIV infection. In the second column, men randomised to VMMC
information believed that women were over 5 percentage points less likely to contact HIV
after sleeping with a seropositive circumcised versus uncircumcised man. Both of these
estimates are similar to those from the simple comparison of means across the treatment
and control group, which adds confidence that assignment to treatment was orthogonal to
measured and unmeasured confounders.
Columns 3 and 4 present results for the second set of models. In both cases,
including a binary indicator for believing that circumcision protected men from contracting
HIV from a seropositive woman led to large absolute declines in the treatment group
coefficient. Those men who believed in the protective benefits of circumcision for men were
64 percentage points more likely (p<0.01) to also believe that male circumcision lowers a
woman’s risk of HIV infection. In addition, the belief that circumcised men were protected
from HIV was associated with a 21 percentage point greater risk reduction (p<0.01) in the
probability of HIV transmission from men to women than men who did not believe that
VMMC protects men.
The last two columns present the IV results. The results in column 5 indicate that
men who were informed about VMCC and believed that male circumcision partially protects
men from HIV infection were 82 percentage point more likely than their counterparts to
believe that male circumcision lowers a woman’s risk of HIV infection (p<0.01). Column 6
shows that the same men inferred that male circumcision protects women by 45 percentage
points (p<0.01), or that male circumcision reduced the per act risk of female HIV
transmission by over 50%. Notably, the first stage Wald F-statistic for these IV regressions
was 15.73, implying that weak instrument bias is not an issue for the coefficient estimates
[23].
6
Discussion
Large-scale public health programs often involve education and information
dissemination efforts in order to affect behaviour change or generate demand for health
products. Their success depends on how individuals internalise the messages and thereafter
act on them. However, it is also possible that individuals infer aspects from these messages
that are not correct, which could undermine the efficacy of such campaigns. In this study,
we examined what individuals learn from information campaigns highlighting the protective
benefits of male circumcision in reducing HIV risk among men. Previous research in rural
Malawi has shown that men correctly internalise the protective benefits of VMMC in
response to a randomly assigned information campaign built around this message [13]. This
study builds on this work and demonstrates that the same men also incorrectly infer that
male circumcision protects women from contracting HIV, despite the lack of any explicit
statement about female risk in the information campaign. Furthermore, the perceived
degree to which VMMC reduces a woman’s risk of HIV infection was large, in the order of
50%.
Recent qualitative studies [15,16] and an opinion and beliefs poll [17] have
suggested that many individuals believe that male circumcision directly reduces a woman’s
risk of HIV infection, but until now evidence from observational studies or randomised
controlled trials has been lacking. Our study presents the first evidence from a randomised
controlled trial on incorrect inferences made from information about VMMC. However, our
study also has some important limitations. First, we do not know what other circumcisionrelated messages participants received during the study period. It is possible that media
campaigns directly stated that VMMC protects women. However, unless outside messages
were delivered differentially across the treatment groups, the internal validity of our
analysis is not threatened. Second, our data come from a sample of rural men and our
findings may not be applicable in other populations. However, one sign that mistaken
inferences may be generalisable is that we found no differences in the likelihood of making
incorrect inferences about HIV risk across differences in education, wealth, and access to
media (available upon request), which is similar to recent findings in South African data [17].
Importantly, there were also no differences in the proportion of men and women holding
incorrect beliefs in the South African data [17], which indicates that women are making
similar incorrect inferences.
Our results have a number of implications for public health policy. Mainly, the
findings demonstrate that individuals may actively project the messages of information
campaigns to groups that do not actually benefit from a particular intervention or change in
behaviour. In our study the proportion of individuals making incorrect inferences was
substantively large. Given that the majority of public health prevention-messages for
diseases which affect both men and women apply to both groups, incorrect inferences may
be especially common in cases where a disease affects both men and women but a public
health message only applies to one gender. Thus, VMMC information campaigns, now being
rolled out across sub-Saharan Africa, and prevention campaigns more generally should be
clear about who benefits from the specific interventions they promote, and who does not.
Along these lines, we believe that future research should focus on two areas. The
first is to assess whether incorrect inferences are made in other public health settings. The
second is to better understand when and how incorrect inferences about VMMC and female
7
HIV risk are formed, especially among women, and the behavioural consequences of such
inferences. Risk compensations stemming from incorrect inferences that VMMC offers
women some protection against HIV could reduce the efficacy of VMMC campaigns and
other HIV prevention efforts. This causal pathway could explain recent results showing risk
compensatory behaviours among women informed about the protective benefits of
circumcision [24,25], particularly in the context of population level data showing that a
significant minority of both men and women believed that VMMC directly protects women
in at least one setting [17].
Large-scale information campaigns will continue to be a mainstay of
prevention efforts. Indeed, VMMC programs in sub-Saharan Africa are using such campaigns
to increase demand for male circumcision services. Specific to these campaigns, our
evidence strongly suggest that educational messages should explicitly state that at present
there has been no significant relationship found between VMMC and direct protection for
women. In addition, we recommend further research into what individuals learn and infer
from public health education messages more generally, and how these messages can be
better tailored to prevent incorrect inferences and potentially thereby enhance their
efficacy.
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10
Figure 1: Standardized information sheet received by participants in the treatment group
11
Table 1: Descriptive Statistics and Differences in Outcomes by Treatment and Control Group
Treatment
(n=466)
Mean (SD) or
%
31.5 (0.31)
5.7 (0.16)
*14730 (877)
4.2 (0.1)
64%
74%
Control
(n=451)
Mean (SD) or
%
31.9 (0.32)
6.1 (0.17)
15236 (789)
4.6 (0.1)
63%
72%
Diff.
P-val.
0.4
0.4
506
0.4
0.5%
2%
0.36
0.08
0.66
0.002
0.86
0.33
Household owns a TV
Listen to radio daily
HIV transmitted by mosquitoes or through kissing
3.20%
53%
65%
3.50%
53%
62%
0.30
%
0.4%
4%
0.78
0.9
0.23
Perceived male HIV risk
Baseline (2008)
†
Number (0-100) of uncircumcised men infected with HIV (2008)
†
Number (0-100) of circumcised men infected with HIV (2008)
Believed male HIV risk is lower for circumcised men (2008)
Follow-up (2009)
†
Number (0-100) of uncircumcised men infected with HIV (2009)
92 (19)
81 (30)
32%
90 (21)
82 (29)
31%
2
1
1%
0.22
0.64
0.78
88 (21)
89 (20)
1
63 (34)
71 (33)
8
65%
50%
14%
0.31
<0.00
1
<0.00
1
Perceived female HIV risk (2009)
†
Number of women (0-100) infected with HIV, partner
uncircumcised
†
Number of women (0-100) infected with HIV, partner
circumcised
90 (20)
89 (20)
1
0.65
72 (32)
78 (30)
6
Believed female HIV risk is lower with a circumcised man
Female risk differential with circumcised vs uncircumcised man
50%
-17 (25)
38%
-11 (22)
12%
6
<0.01
<0.00
1
<0.01
Treatment
(n=301)
Mean (SD) or
%
73%
Control
(n=227)
Mean (SD) or
%
70%
Diff.
P-val.
4%
0.33
-26 (26)
-21 (26)
5
0.04
Estimation sample
Age
Years of education
Monthly household income (Kwacha)
Household asset index (0-13)
Farmer
Circumcised
†
Number (0-100) of circumcised men infected with HIV (2009)
Believed male HIV risk is lower for circumcised men (2009)
Sample who believed that male HIV risk is lower for circumcised
men (2009)
Believed female HIV risk is lower with a circumcised man
Female risk differential with circumcised vs uncircumcised man
Notes: P-value derived from two-sample differences in means or proportion test across groups.
*The Malawian Kwacha to US Dollar exchange was 0.007036 on October 31, 2008, so K14730 was equivalent to $104.
†
All HIV risk variables based on unprotected sex with an HIV-positive person of the opposite sex. See main text for details.
The difference column does not always equate to difference between the figures displayed for the treatment and control group
because all figures have been rounded to the nearest integer.
12
Table 2: Multivariate Ordinary Least Squares (OLS) and Instrumental Variable (IV) models for beliefs about male circumcision and a woman’s risk of HIV
infection.
Model:
Dependent variable:
Treatment group (=1)
Believed male HIV risk is lower for circumcised men (2009)
(1)
OLS
(2)
OLS
Believed risk is lower Risk differential
0.102**
-5.592***
(0.042)
(1.815)
Believed male HIV risk is lower for circumcised men (2008)
Circumcised (2008)
Age
Years of education (2008)
Literate in Chichewa (2008)
Household assets (2008)
Logged monthly household income (2008)
Number of HIV messages heard on radio (2008)
Believed HIV transmitted via mosquito or kissing (2008)
0.149***
(0.032)
-0.005**
(0.002)
-0.005
(0.006)
0.016
(0.051)
-0.0151*
(0.008)
0.010
(0.012)
-0.001
(0.001)
-0.012
(0.031)
-6.818***
(1.507)
0.092
(0.120)
0.132
(0.283)
-0.136
(2.507)
0.556
(0.374)
-0.044
(0.606)
0.070
(0.052)
0.093
(1.645)
(3)
OLS
Believed risk
is lower
0.022
(0.032)
0.638***
(0.028)
0.018
(0.033)
0.012
(0.021)
-0.001
(0.002)
0.002
(0.005)
-0.027
(0.039)
-0.010
(0.006)
0.005
(0.007)
-0.001
(0.001)
0.001
(0.023)
(4)
OLS
Risk
differential
-2.955**
(1.437)
-21.14***
(1.523)
-1.573
(1.908)
-2.154
(1.414)
-0.043
(0.100)
-0.114
(0.251)
1.338
(2.188)
0.380
(0.304)
0.130
(0.489)
0.0796*
(0.046)
-0.375
(1.469)
(5)
IV
Believed risk
is lower
(6)
IV
Risk
differential
0.817***
(0.249)
-0.023
(0.066)
-0.021
(0.045)
0.000
(0.002)
0.004
(0.006)
-0.036
(0.044)
-0.008
(0.007)
0.003
(0.008)
-0.001
(0.001)
0.002
(0.023)
-45.07***
(11.540)
3.905
(3.540)
2.222
(2.470)
-0.172
(0.122)
-0.350
(0.295)
2.545
(2.337)
0.177
(0.362)
0.361
(0.532)
0.082
(0.053)
-0.486
(1.696)
Robust standard errors, clustered at the respondent village level (69 clusters) in parentheses.
*** - p<0.01, ** - p<0.05, * - p<0.01
Dependent variables: (1) “Believed risk is lower” is the proportion of men that believed that a woman’s risk of HIV infection is lower with a circumcised man. (2) “Risk differential” is the
difference in perceived HIV transmission risk from males to females between circumcised and uncircumcised sexual partners.
Treatment group = 1 if the respondent was randomly assigned to receive VMMC prevention information. The rest of the variables are defined in the main text.
13
Appendix
Figure A1: Poster distributed in Zambia to increase awareness about Male Circumcision
and HIV prevention
(Downloaded from “Clearinghouse on Male Circumcision for HIV Prevention” website:
http://www.malecircumcision.org/programs/mass_media_materials.htm, 15 April 2013)
14
Table A1: Additional baseline characteristics by randomisation to treatment
Married
Christian
Muslim
Tribe:
Nyanja
Yao
Lomwe
Chewa
Literacy in Chichewa
Literacy in English
treatment (n=466) control (n=451)
%
%
91
88
56
52
37
40
42
32
21
4
77
34
42
37
13
6
77
39
difference
%
3
4
2
p-value
0
5
7
1
0
5
0.98
0.11
<0.01
0.38
0.96
0.14
0.18
0.24
0.46
15
southern africa labour and development research unit
The Southern Africa Labour and Development Research Unit (SALDRU) conducts research directed at
improving the well-being of South Africa’s poor. It was established in 1975. Over the next two decades the
unit’s research played a central role in documenting the human costs of apartheid. Key projects from this
period included the Farm Labour Conference (1976), the Economics of Health Care Conference (1978), and
the Second Carnegie Enquiry into Poverty and Development in South Africa (1983-86). At the urging of the
African National Congress, from 1992-1994 SALDRU and the World Bank coordinated the Project for Statistics
on Living Standards and Development (PSLSD). This project provide baseline data for the implementation
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