POVERTY, GENDER, AND YOUTH
Sexual Behavior and STI/HIV Status Among Adolescents
in Rural Malawi: An Evaluation of the Effect of
Interview Mode on Reporting
Barbara S. Mensch, Paul C. Hewett, Richard Gregory, and Stephane Helleringer
WORKING PAPER NO. 8 2008
One Dag Hammarskjold Plaza
New York, New York 10017 USA
For information on Poverty, Gender, and Youth working papers, see
This material may not be reproduced without written permission from the authors.
© 2008 The Population Council, Inc.
Sexual Behavior and STI/HIV Status Among Adolescents in Rural Malawi:
An Evaluation of the Effect of Interview Mode on Reporting
Barbara S. Mensch
Paul C. Hewett
Barbara S. Mensch is Senior Associate and Paul C. Hewett is Associate, Poverty, Gender, and
Youth Program, Population Council. At the time this paper was written, Richard Gregory was
Research Coordinator and Data Analyst, Policy Research Division, Population Council. He is
currently affiliated with the UK Department for International Development. Stephane Helleringer
is a postdoctoral researcher at the University of Pennsylvania Population Studies Center,
This is a revised version of a paper presented at the Annual Meeting of the Population
Association of America, Los Angeles, 31 March 2006; the MDICP miniconference, Philadelphia,
13 October 2006; and the International Union for the Scientific Study of Population seminar on
Sexual and Reproductive Transitions to Adulthood in Developing Countries, Mexico, 6–9
The research was supported by grants from the National Institutes of Health to the authors (R01-
HD-047764-01) and to the Population Studies Center, University of Pennsylvania (R01-HD-
044228-01). Support was also provided by the Hewlett Foundation, the Department for
International Development, UK Office of Population and Reproductive Health, and the Bureau
for Global Health, the United States Agency for International Development, under the terms of
Award No. HRN-A-00-99-0010. The authors thank Susan Watkins for her comments and extend
special thanks to our Malawian supervisors Praise Chatonda and Adam Yasin, to Dowd Rashid,
and to the data-collection team, whose very hard work made the study possible.
The opinions expressed herein are those of the authors and do not necessarily reflect the views of
the United States Agency for International Development.
Our understanding of the dynamics of HIV transmission in developing countries is
compromised by unreliable data concerning sexual behavior. This paper represents an effort to
investigate young people’s reporting of sexual behavior. It summarizes the results from an
interview-mode experiment conducted with unmarried young women aged 15–21 in rural
southern Malawi in which respondents were randomly assigned to either an audio computer-
assisted self-interview (ACASI) or a conventional face-to-face (FTF) interview. In addition,
biomarkers were collected for HIV and three STIs: gonorrhea, chlamydia, and trichomoniasis.
Prior to collecting the biomarkers, nurses conducted a brief face-to-face interview with
participants in which they repeated questions about sexual behavior asked earlier. The paper
builds on earlier research among adolescents in Kenya where we first investigated the feasibility
and effectiveness of ACASI. In both Kenya and Malawi, clear evidence indicates that the mode
of interviewing and probing concerning various sexual partnerships affects respondents’
reporting of their sexual activity. Yet, the results are not always in accordance with expectations.
Reporting for “ever had sex” and “sex with a boyfriend” is higher in the FTF mode. When we
ask about other partners as well as multiple lifetime partners, however, the reporting is
consistently higher with ACASI, in many cases significantly so. As in Kenya, in Malawi the
interview-administered mode produced more consistent reporting of sexual activity between the
main interview and a subsequent interview. Finally, the association between infection status and
reporting of sexual behavior is stronger in the FTF mode, although in both modes, some young
women who denied ever having had sex tested positive for STIs/HIV.
Our understanding of the dynamics of HIV transmission in developing countries is
compromised by unreliable data on sexual behavior. Epidemiological studies in Africa have
observed little association between self-reported risky sexual behavior and HIV status. Indeed, a
large multisite study of factors determining HIV prevalence in four African cities revealed
considerable numbers of women who were HIV-positive yet reported themselves to be virgins or
reported having only one sexual partner and few episodes of sexual intercourse (Buvé et al. 2001;
Glynn et al. 2001).
The inconsistency between reported sexual behavior and HIV incidence has prompted
some epidemiologists to question the conventional explanation for the African AIDS pandemic.
Arguing that preconceived notions of African sexuality have unduly influenced researchers,
several epidemiologists suggest that parenteral transmission via medical injections with
contaminated needles rather than risky sexual behavior has played a substantial role in the spread
of HIV (Brewer et al. 2003; Gisselquist et al. 2003; Gisselquist and Potterat 2003).1 Some
anthropologists also have been critical of the standard interpretations for the African pandemic.
In a recent critique of explanations for trends in HIV transmission in Uganda, Tim Allen
(2006:14) argues that “much of what has been claimed [about sexual activity] is based on little
more than speculation, and is sometimes affected by very misleading assumptions about a
homogeneous African sexuality.” He also faults AIDS researchers for focusing on high-risk
behavior and neglecting nonsexual transmission.
Surprisingly, the epidemiologists who challenge conventional wisdom about the AIDS
pandemic in Africa are not similarly skeptical about the survey data concerning sexual behavior
that are used to buttress their arguments. Gisselquist and Potterat (2003:171) assert: “[T]he care
with which these [surveys] . . . have been performed, the familiarity of investigators with local
conditions, their experience in the conduct of such studies, and the consistency of response make
summary dismissal of such results untenable.” The willingness of these researchers to accept
survey data of questionable validity has serious implications for interpretations of the etiology of
Researchers who rely on survey data are more suspicious of the information they collect
than are the epidemiologists cited above. With regard to the sexual behavior of adolescent girls in
sub-Saharan Africa—the subject under investigation here—it is reasonable to expect that a
substantial number of young women would find great difficulty admitting to an interviewer that
they have had sex outside of a socially sanctioned relationship (Dare and Cleland 1994).
Throughout much of the region, the Catholic Church and evangelical Protestant churches have a
prominent role in the lives of the population, premarital abstinence is increasingly promoted, and
the discovery of a pregnancy often means the girl’s expulsion from school.
Watkins and her colleagues (2003) have observed that a well-designed and carefully
followed data-collection process does not guarantee that good data will be obtained. Despite
attention to questionnaire development and to selection, training, and supervision of interviewers
in their own surveys in Kenya and Malawi, they found evidence of “patron–client relations,
respondent autonomy and interviewer autonomy,” all of which undermine data quality.2 They
advocate that “research not only attempt to uncover systematic biases in the data but also that a
description of data collection procedures and evaluation of data quality become a routine
expectation for research articles” (pages 27–28).
Researchers have examined the reliability and validity of survey data collected in
developing countries (Blanc and Rutenberg 1990; Lagarde et al. 1995; Blanc and Way 1998;
Eggleston et al. 2000; Curtis and Sutherland 2004; Gregson et al. 2004; Nnko et al. 2004; Zaba et
al. 2004). Although many acknowledge that the reporting of sexual behavior is problematic, few
have investigated the ways in which the data-collection process may be flawed and explored
techniques to improve it. Gregson and his colleagues (2002) and Plummer and colleagues (2004),
together with the researchers who have conducted the interview-mode experimental studies
described below, are notable exceptions.
In 2003, a technical meeting on “Measurement of Trends in Sexual Behaviour,” co-
sponsored by the London School of Hygiene & Tropical Medicine, UNAIDS, the World Health
Organization (WHO), and the MEASURE Project, was convened to review the quality of data
used to assess trends in sexual behavior in the context of the HIV pandemic and to examine
various methodologies to collect sexual behavior data in surveys. Although the goal was to
develop recommendations for monitoring trends in sexual behavior, no simple guidelines
emerged (see Cleland et al. 2004). The takeaway message from the meeting was that more
studies must be conducted before definitive claims can be made about the best way to collect data
on sexual behavior.
This paper represents an effort to investigate the reporting of sexual behavior in a
developing country survey. It summarizes the results from an interview-mode experiment
conducted among unmarried adolescents in a rural district of southern Malawi. Data on sexual
behavior generated from audio computer-assisted self-interviewing (ACASI), a technique
designed in the United States to collect information about sensitive issues, are compared with
data generated from conventional face-to-face (FTF) interviews. The paper builds on earlier
research conducted in two districts in Kenya where we first investigated whether use of ACASI
is feasible in developing countries and whether it is a superior method of data collection to
interviewer- and self-administered questionnaires (Mensch et al. 2003; Hewett et al. 2004a and
2004b). Although the software and hardware performed well in Kenya, and ACASI was found to
elicit higher reporting for many questions on sensitive behavior, some anomalies emerged that
raised questions about the effectiveness of computerized interviewing for reducing measurement
error in developing country surveys.
One of the limitations of our Kenya study was that we could determine only if reporting
in the two interview modes differed statistically from each other. For the Malawi analysis
presented here, we use biomarkers of STIs and HIV to investigate the strength of the association
between STI/HIV status and risky sexual behavior according to interview mode. Although we are
aware of the limitations and difficulties of using biomarkers to assess reporting of sexual
behavior (Catania et al. 1990; Fishbein and Pequegnat 2000; Fenton et al. 2001), we believe that
when they are collected in tandem with an experimental assignment to interview mode, they can
provide important supplementary data for evaluating interviewer-mode effects.
LITERATURE REVIEW: THE REPORTING OF SEXUAL BEHAVIOR WITH ACASI
The computerized administration of questionnaires, developed in part to address concerns
about the influence of interviewers in surveys, hypothesizes that the more private and
standardized the interview, the better the quality of the data. With ACASI, software is designed
so that the respondent hears both the question and the response categories through headphones.
The respondent answers each question by pressing a number on a keypad or computer keyboard.
The advantage of ACASI over FTF interviews is that neither the investigator nor anyone else in
the area where the interview is being conducted hears the question or the response, thus reducing
social desirability bias. Moreover, unlike self-administered interviewing, which requires that the
respondent be literate and competent to fill out a questionnaire, ACASI can be used without the
respondents’ having to read the questions on the computer screen.3 Additionally, the researcher
does not have to be concerned with differences in the characteristics or interviewing styles of the
interviewers (Tourangeau et al. 2000). In situations where respondents are forthcoming about
sensitive behaviors, however, removing the interviewer may have consequences for data quality,
because a competent interviewer can probe, assist with recall, and resolve inconsistencies.
ACASI has been used successfully in United States surveys, including the National
Survey of Family Growth, the National Survey of Adolescent Males, and the National
Longitudinal Study of Adolescent Health. Data have been collected on the use of injectable
drugs, abortion, same-gender sex, and violent behavior—with significantly higher levels of these
behaviors reported than in face-to-face interviews and paper-and-pencil self-administered
questionnaires, although ethnic differences in the degree of respondents’ comfort with the
computer have been noted (Tourangeau and Smith 1996; Turner et al. 1997; Fu et al. 1998;
Turner et al. 1998; Hewitt 2002). ACASI also has been used successfully in specialized surveys
of gay men, injecting drug users, and women at high risk of HIV exposure (Des Jarlais et al.
1999; Gross et al. 2000; Metzger et al. 2000). Randomized assignment of respondents to either
ACASI or face-to-face interviews revealed greater reporting of HIV risk behaviors with the
computer (Des Jarlais et al. 1999; Metzger et al. 2000), with greater differences being observed
among HIV-positive than HIV-negative respondents (Macalino et al. 2002).
A commentary in Science, summarizing the results of an experiment conducted in the
United States comparing ACASI with self-administered questionnaires, argued that ACASI may
be especially suited to collecting data in developing countries, “where overcrowded living
conditions typically prevail, where literacy is relatively low, and where some of the behaviors in
question may be particularly pronounced” (Bloom 1998:847). In the past five years, a number of
studies have investigated the use of ACASI in developing countries. The results from this
research are not as definitive, however, as the results from the interview-mode experiments in the
One of the first experiments conducted outside the United States was carried out at a
college in Thailand; it compared self-administered questionnaires with ACASI. Substantial
differences in responses were found according to interview mode: ACASI produced more reports
of sexual activity, particularly for females, although the sample was too small for these
differences to be statistically significant. The researchers’ use of automated skip patterns with
ACASI reduced measurement error (Rumakom et al. 1999). A more recent randomized
experiment in Thailand was conducted among a sample of more than 1,200 students aged 15–21.
The study compared palm-top assisted self-interviewing (PASI) with ACASI, self-administered,
and face-to-face interviewing and found that PASI was comparable to ACASI and self-
administered questionnaires and superior to face-to-face interviews with regard to self-reports of
the most sensitive sexual behaviors. Moreover, the association of tobacco smoking as reported by
the respondent with a biomarker for nicotine metabolites in urine was stronger in PASI and
ACASI than in face-to-face interviews (van Griensven et al. 2006).
A study in Mexico assessed differences in the reporting of induced abortion by women
aged 15–55 who were randomly assigned to one of four interview methods: ACASI using a touch
screen, face-to-face interviews, self-administered interviews, and a random-response technique.
For the random-response technique, a woman was asked to put her hand in a bag that contained
two folded sheets of paper, one asking whether she was born in April and the other asking
whether she had ever had an abortion. The interviewer did not know which sheet the woman
chose. The methods were tested among three populations: hospital patients in Mexico City,
women in a rural area, and women in a household sample in Mexico City. For all three
populations, the highest reported rate of abortion was found with the random-response technique,
followed by the self-administered questionnaire. Reporting among those assigned to ACASI and
face-to face interviews was lower (Lara et al. 2004).4
Two experimental studies with random assignment have been conducted more recently in
Asia, one in Pune, India, among unmarried male college students and slum dwellers, and another
in Vietnam among a large household-based sample of adolescents in a suburb of Hanoi. In India,
reporting of sensitive sexual behaviors was generally higher among college students assigned to
ACASI, compared with those assigned to face-to-face or self-administered questionnaires. The
results for young slum dwellers were much less consistent, which led the authors to question the
efficacy of computerized interviewing among the less-educated (Potdar and Koenig 2005). In
Vietnam, the reporting of sensitive behavior was significantly higher among young men assigned
to ACASI, but not among young women (Linh et al. 2006).
Our research in Kenya employed an experimental design to investigate whether ACASI
produced reporting of sexual activity and related behaviors of greater validity than did FTF
interviews or self-administered interviews among more than 6,000 unmarried adolescents aged
15–21 in two districts. The results for girls from the first district, Nyeri, were inconsistent with
expectations. In response to the initial “ever had sex” question, girls interviewed with the
computer were less likely to report that they had had sex, compared with those interviewed face-
to-face. Boys interviewed with ACASI were also less likely to report having had sex, but that
was an expected finding, because we assumed that boys exaggerate in FTF interviews. For the
second district, Kisumu, we altered the skip pattern of the questionnaire. Regardless of the
response to the first question, respondents were asked a subsequent series of questions about
sexual partners and coerced sex. For most of these additional questions, which ask about more
stigmatized behavior, reporting was higher among both boys and girls when the computer was
used (Mensch et al. 2003).
A more focused analysis of consistency in the reporting of sexual behavior among
adolescent girls in Kisumu revealed that ACASI respondents were much less likely than those
interviewed face to face to provide consistent answers. For example, only three of 181 young
women interviewed face to face who reported never having had sex in response to the first
question about sexual behavior indicated that they had had sex in response to questions about
various types of partners and experience of coerced sex.5 In contrast, among the ACASI group,
83 of the 174 respondents who reported never having had sex subsequently reported having had
sex in answer to the partner and coerced-sex questions. Based solely on the initial question of age
at first sex, 48 percent of the interviewer-administered group reported having had sex, compared
with 43 percent of the ACASI group. When we recomputed the proportion who had ever had sex
based on all of the sexual behavior questions, the interviewer-administered group barely changed
(49 percent), whereas the ACASI group increased to 68 percent. We concluded that ACASI
produced a more diverse picture of adolescent sexual activity than FTF interviews. We also
concluded that the consistency in the FTF interview mode was suspect, particularly given the
much lower levels of reporting, relative to ACASI, for types of sexual partners and coerced
sexual activity (Hewett et al. 2004b).
DATA COLLECTION AND SAMPLE
The ACASI experiment described here was an ancillary study to the 2004 wave of the
Malawi Diffusion and Ideational Change Project (MDICP), a panel survey of ever-married
women of childbearing age and their husbands to which an adolescent sample was added. The
MDICP assesses behavioral responses to perceived and actual HIV/AIDS risk, with a conceptual
focus on the role of social interactions in mediating information flows.6 The first MDICP survey
was conducted in 1998 in rural areas of three districts of Malawi, one in each administrative
region of the country, Rumphi in the north, Mchinji in the center, and Balaka in the south.
Although the MDICP survey was not designed to be representative of rural Malawi, the sample
characteristics are similar to those of the rural areas represented in the 1996 Malawi
Demographic and Health Survey (Watkins et al. 2003). A second round of the survey was
conducted in 2001 and the third in 2004. For the third wave of data collection, approximately
1,500 unmarried and married males and females aged 15–24 were added to the study population;
participants of all ages were tested for HIV, chlamydia, and gonorrhea, and the women were also
tested for trichomoniasis.
The data for the ancillary study come from interviews conducted in June and July of 2004
among a supplementary sample of 5017 unmarried female adolescents mostly aged 15–218 in
rural areas of Balaka District. Balaka was selected because it lies in the region of the country
with the highest reported rates of HIV infection (UNAIDS 2004), teenage pregnancy, risky
sexual behaviors, and early sexual initiation (National Statistical Office [Malawi] and ORC
Macro 2001). Although the Chewa are the most populous ethnic group in Malawi, the dominant
group in Balaka is the Yao. More than half of the adolescents in our sample are Yao, 15 percent
are Chewa, nearly 20 percent are Ngoni, and the remainder identify with a variety of other tribes.
Like the Chewa, the Yao speak a Bantu language and follow a matrilineal system of inheritance.
The Ngoni, who migrated from South Africa at the beginning of the nineteenth century, were
originally patrilineal with patrilocal marriage. Because they have intermarried with matrilineal
groups, however, they have not retained their original customs. Moreover, because of contact
with other groups, they no longer speak a Zulu dialect; virtually all of the Ngoni in our sample
speak Chichewa. Unlike the Chewa and Ngoni, who are almost all Christian, the Yao are
primarily Muslim, their ancestors having come into contact with Arab/Swahili slave traders in
Mozambique during the nineteenth century (Tew 1950).
The adolescents in our sample resided in villages contiguous to trading centers near the
villages included in the main MDICP. Trading centers in rural Malawi consist of small
centralized market areas and are typically situated along major roadways. The villages adjacent
to trading centers are more densely populated than remote rural villages and were chosen because
of the greater likelihood of finding adolescents, who are typically more mobile than the adult
population. Nonetheless, despite our efforts, the response rate was not high. Of the 707
adolescents in our household listing, 501 were interviewed successfully, a response rate of 71
percent. We have no way of knowing whether those who were interviewed differed markedly
from those who were not, because household information was not included systematically in the
listing form. The MDICP household form was used only for determining eligibility. As for the
characteristics of the households in our sampled communities, few had access to electricity or
piped water, and homes were typically made of sun-dried brick covered with mud and thatched
roofs. The primary economic activity in these communities is subsistence agriculture.
Respondents were randomly assigned to either a complete face-to-face interview or a
FTF/ACASI combination interview. The questionnaire for the experimental substudy was the
same as that used for the adolescent sample in the MDICP survey. The 12 sections of the
questionnaire were divided by topic; the sexual behavior questions were in section 6. For ACASI
respondents, all sections except for the sexual behavior questions and a small set of sensitive
questions from the HIV/AIDS section were administered face to face by an interviewer. To
further minimize the effect of interviewer characteristics, all interviewers were female and
trained in both interview methods; respondents were randomized to an interviewer and to an
After an introduction that reiterated the confidentiality of the interview and the purpose of
collecting sensitive information, the sexual behavior section began with a question on age at first
sex and continued with questions about different types of sex partners (person the respondent was
expected to marry [“expected spouse”], boyfriend, friend or acquaintance, relative, teacher,
employer, or stranger). As in our Kisumu, Kenya study, the follow-up partner questions were
asked regardless of the response to the initial sexual behavior question. If a respondent indicated
that she had had sex with a particular partner, she was asked the age at which she first had sex
with that partner. Additional questions included the total number of lifetime sexual partners, and
whether the respondent had had sex in the past 12 months. If respondents replied that they had
had any sex partners, they were asked a series of questions about their two most recent partners,
including frequency of sex, duration of the relationship, marital status of the partner, educational
level of the partner, and condom use, including ever use, use at last sex, and frequency of use.
After being interviewed, respondents were asked whether they would be willing to be
tested for HIV and STIs. Consent was requested separately for HIV and the STIs, and parental
permission was obtained for those adolescents younger than 18. Testing for STIs typically
occurred within one week of the survey and was conducted by trained nurses. Prior to collection
of the biomarkers, each respondent was interviewed by the nurses and asked again the series of
questions about sexual behavior, including age at first sex, number of sex partners, sex in the past
12 months, relationship to current or most recent sexual partner, condom use at last sex, whether
she had overlapping partners, and whether she had been tested for HIV. These questions enable
us to perform test–retest comparisons of the consistency of responses by interview mode.