THE IMPACT OF QUESTIONNAIRE ADMINISTRATION MODE ON RESPONSE RATE AND REPORTING OF CONSENSUAL AND NONCONSENSUAL SEXUAL BEHAVIOR

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1 Psychology of Women Quarterly, 29 (2005), Blackwell Publishing. Printed in the USA. Copyright C 2005 Division 35, American Psychological Association /05 THE IMPACT OF QUESTIONNAIRE ADMINISTRATION MODE ON RESPONSE RATE AND REPORTING OF CONSENSUAL AND NONCONSENSUAL SEXUAL BEHAVIOR Maria Testa, Jennifer A. Livingston, and Carol VanZile-Tamsen University at Buffalo Computer-administered self-interviewing (CASI) has been advocated as a way of overcoming underreporting of sensitive sexual behaviors. The present study compared reports of consensual and nonconsensual sexual behaviors (including childhood and adulthood sexual victimization) among women using CASI (n = 1014) versus a self-administered questionnaire (SAQ; n = 318). Women, ages years old, were recruited through random-digit dialing in the community. Response rates were significantly higher for the SAQ, which was sent and returned by mail (87.6% of those eligible), than for the CASI, which involved in-person assessment at a central location (61.4%). There were a few modest differences in reports of consensual or nonconsensual sexual behavior according to mode of administration, suggesting greater willingness to report sexual experiences among the SAQ sample. Mailed SAQ following telephone contact and with financial incentive may be a cost-effective way of obtaining data on sexual behavior from a community sample. The study of sexual behavior, both consensual and nonconsensual, requires reliance on self-reports of behavior. Ensuring accurate and unbiased measurement of sexual behavior is particularly challenging given the private and sensitive nature of this domain and a tendency for most adults to underreport sexual behavior (Catania, Gibson, Chitwood, & Coates, 1990). Self-presentational concerns appear to be heightened with behaviors that are considered least socially desirable, such as anal sex, resulting in the greatest degree of underreporting (Downey, Ryan, Roffman, & Kulich, 1995). Because of the lasting influence of the sexual double standard, which maintains that sexual behavior is more acceptable for men than for women (e.g., Sheeran, Spears, Abraham, & Abrams, 1996), women may be particularly likely to minimize or fail to report their sexual experiences. Traditionally, survey researchers have advocated the use of self-administered questionnaires, preferably anonymous or private ones, over face-to-face interviewing as a way of Maria Testa, Jennifer A. Livingston, and Carol VanZile-Tamsen, Research Institute on Addictions, University at Buffalo. This research was supported by grants R01 AA12013 from the National Institute on Alcohol Abuse and Alcoholism and NIH Director s Office of Research on Women s Health and K02 AA00284 from the National Institute on Alcohol Abuse and Alcoholism. Address correspondence and reprint requests to: Maria Testa, Research Institute on Addictions, 1021 Main Street, Buffalo, NY testa@ria.buffalo.edu minimizing the tendency to underreport socially undesirable behaviors (Sudman & Bradburn, 1983). Compared to face-to-face interview, self-administered questionnaires (SAQ) result in increased reporting of sensitive behaviors such as illicit drug use (Schober, Caces, Pergamit, & Branden, 1992; Turner, Lessler, & Devore, 1992), and among women, abortions and number of sexual partners (Schaeffer, 2000). Recently, many researchers have begun to use computer-assisted self-administered interviewing (CASI), in which interview questions appear on a screen and participants answer them privately. Audio-CASI, in which a recorded voice reads the questions as they are presented on the screen to overcome literacy difficulties is another variation. This mode of administration has been advocated as an additional and potentially superior method of enhancing privacy, thereby reducing underreporting of sensitive behaviors (Tourangeau & Smith, 1996). Several studies indicate that use of CASI or Audio-CASI results in a greater proportion of individuals reporting highly sensitive behaviors such as illicit drug use (O Reilly, Hubbard, Lessler, Biemer, & Turner, 1994; Tourangeau & Smith, 1996) and HIV risk behaviors (DesJarlais et al., 1999; Locke et al., 1992) compared to a face-to-face interview (see Gribble, Miller, Rogers, & Turner, 1999 for a review). CASI also may result in a greater proportion of individuals reporting sensitive behaviors compared to SAQ (Kissinger et al., 1999; O Reilly et al., 1994; Paperny, Aono, Lehman, Hammar, & Risser, 1990), although not all studies have found a clear advantage to CASI (e.g., Hallfors, 345

2 346 TESTA ET AL. Khatapoush, Kadushin, Watson, & Saxe, 2000; Webb, Zimet, Fortenberry, & Blythe, 1999; Williams et al., 2000). It is possible that CASI reduces impression management concerns and increases reporting only for the most sensitive of behaviors. For example, among adolescent males, higher reports using CASI compared to SAQ were specific to the most sensitive behaviors, such as sex with a prostitute and sex with men, and were not apparent for reports of more common heterosexual behaviors (Turner et al., 1998). Although several studies have compared the effects of mode of administration on reporting of substance use and sexual behavior, we are unaware of any studies that have examined these effects with respect to experiences of nonconsensual sexual experiences among women. It has generally been assumed that rape and other sexual victimization experiences are underreported and that care is necessary to minimize this bias (Hardt & Rutter, 2004; Koss, 1993). Use of multiple, behaviorally specific questions that avoid emotionally charged labels such as rape has been advocated as one way of increasing the accuracy of self-reported sexual victimization (Fisher, Cullen, & Turner, 2000; Koss, 1993). To this end, the Sexual Experiences Survey (SES; Koss, Gidycz, & Wisniewski, 1987) was developed as a 10-item self-administered questionnaire. Similarly, childhood sexual abuse experiences have been assessed using a series of behaviorally specific questions (e.g., Finkelhor, 1979; Wyatt, Loeb, Solis, & Carmona, 1999). Prevalence rates of childhood sexual abuse are higher when multiple questions, rather than single or gateway questions are used (Goldman & Padayachi, 2000; Williams, Siegal, & Pomeroy, 2000). CASI administration of these questions may result in a greater proportion of women reporting sexual victimization experiences relative to a self-administered questionnaire, although to our knowledge, there have been no direct comparisons of CASI versus SAQ methodology for women s sexual victimization experiences. The first purpose of the present study was to compare reports of consensual and nonconsensual sexual experiences for questionnaires administered by CASI versus SAQ among a community sample of young women. We tentatively hypothesized that CASI would increase women s willingness to report sexual risk taking and sexual victimization. We expected that mode reporting differences were most likely to be apparent for highly sensitive behaviors, such as sex in exchange for money or drugs. A second goal of the study was to compare response rates for women offered the opportunity to participate in a CASIadministered session followed by an interview at a central location versus to complete an SAQ at home and return it by mail. High response rates are critical to obtaining accurate estimates of the prevalence of sexual behaviors (Catania et al., 1990). Studies that have used random-digit dialing (RDD) to recruit participants for an in-person assessment at a central location have been able to achieve response rates as high as 81.7% of eligible participants with use of a financial incentive (e.g., Abbey, BeShears, Clinton-Sherrod, & McAuslan, 2004; Cooper, Peirce, & Huselid, 1994). We are unaware of any researchers who have recruited through RDD but then sent a mailed survey. With use of a comparable incentive, one might expect a higher response rate with this method, given that less effort is required to complete a questionnaire at home compared to traveling to a central location. However, response rates for surveys completed by telephone are typically lower than those for inperson assessment (about 65%), even though length is typically shorter and effort considerably lower (e.g., Wells & Graham, 2003; Welte, Barnes, Wieczorek, Tidwell, & Parker, 2001). Studies involving mailed surveys have been able to achieve high response rates with use of a cover letter, incentives, and reminders (Dillman, 1983; Gore- Felton, Koopman, Bridges, Thoresen, & Spiegel, 2002). Using these techniques, we examined the response rate for SAQ sent and returned by mail compared to in-person assessment at a central location. Sampling, method of recruitment, initial description of study content, and financial incentive were identical in the two conditions. A difference in the percentage or type of women willing to participate in one versus another mode of administration provides important practical information on the attractiveness of each method and on potential participation bias associated with the two methods. Because previous studies have not considered response rates associated with SAQ following RDD recruitment, we offered no hypothesis regarding response rate differences. Sample Recruitment METHOD Women were recruited for CASI administration via RDD of households in the Buffalo, New York metropolitan area between May 2000 and April This recruitment was conducted as part of a large study on women s alcohol use and sexual experiences (e.g., Testa, VanZile-Tamsen, Livingston, & Koss, 2004). The sample of telephone numbers was constructed to include all of the city of Buffalo as well as suburbs located primarily within miles of downtown. Telephone interviewers identified themselves as University at Buffalo researchers conducting a brief survey of households in the area and asked whether there were any women ages 18 to 30 in the household. If there was more than one woman between these ages, one was randomly selected. The eligible woman was then asked for her date of birth (to verify eligibility) and marital status and offered the opportunity to participate. Women were told that the study was examining the social experiences of women in the community and that questions would concern personality, alcohol and drug use, and sexual experiences. They were offered $50 for their participation in a 2-hour interview session, conducted at the University Research Institute, located in downtown Buffalo. They were told that participation would involve computer-administered questionnaires as well as a confidential face-to-face interview with a female

3 Impact of Mode on Reporting Sexual Behavior 347 interviewer. Appointments were scheduled at the woman s convenience during day, evening, or weekend hours. To provide a comparison group, a new and separate RDD sample of women, covering the same geographic area, was obtained between May 2002 and October The methodology was identical to that used for the CASI sample; however, eligible women identified during this period were told that the study would involve the completion of a packet of SAQs that they would return in a postage-paid envelope. They were also told that questions would concern personality, alcohol and drug use, and sexual experiences. They were offered $50 for participation and told that the questionnaires would take about 1.5 hours to complete. Procedures CASI sample. Upon arrival at the Research Institute, participants were escorted to a private room with a computer terminal. Study procedures were explained and informed consent was obtained by a female research assistant. Participants were told that some questions might make them uncomfortable and informed that they had the right to refuse to answer any question or to discontinue the questionnaires or face-to-face interview at any time. Refusal options were provided for all CASI questions. The research assistant remained in the room during most of the interview so that she could answer questions or assist with the computer if needed; however, the computer screen was oriented so that she could not see the participant s responses, and she remained engaged in reading or other tasks. A face-to-face interview regarding alcohol consumption was conducted in the middle of two CASI sections, and another interview regarding adult sexual victimization experiences took place at the very end of the session. Questionnaire sections on consensual sexual behavior, childhood sexual abuse, and adult sexual victimization were administered after the alcohol interview, although the order in which these questionnaires appeared was randomized. Women did not know what the interview sections would entail when they were recruited into the study or when they completed the CASI. SAQ sample. Questionnaire booklets were sent to participants homes along with an informed consent form and a letter designed to provide information comparable to that provided to CASI participants. That is, women were informed that they had the right to refuse any question or to withdraw from the study at any time and ensured of the confidentiality of data. They were also provided with a study phone number to call if questions arose. They were instructed not to put their name on the questionnaire booklet and to return the booklet by the date written on the cover (2 weeks). A postage-paid envelope was included for return of the completed booklet and signed consent form. Although SAQs were confidential, data collection could not be anonymous because follow-up phone calls were made and checks were subsequently mailed to participants. Measures CASI questionnaires and SAQs were similar and covered the same content area; however, we omitted some CASI questionnaires from the SAQs because of complicated skip and branching patterns that make them difficult to complete without assistance. Only questionnaires relevant to the present study are described below. Childhood sexual victimization. Women were asked a series of eight questions, adapted from Finkelhor (1979) and Whitmire, Harlow, Quina, and Morokoff (1999) regarding nonconsensual sexual experiences occurring before age 14. These items consisted of: person kissed or hugged you in a sexual way; you touched another s genitals at their request; person attempted to touch you in a sexual way; person touched you in a sexual way; attempted oral, vaginal, or anal sexual intercourse; completed oral, vaginal, or anal intercourse; and vaginal or anal penetration by object. Women who reported one or more of these unwanted experiences before age 14 were classified as experiencing childhood sexual abuse. We also classified women according to whether they had experienced penetrative abuse and nonpenetrative abuse, and computed a sum of childhood sexual abuse experiences. Adult sexual victimization. Women completed a modified 11-item version of the SES (Koss et al., 1987), which included an additional item regarding rape while incapacitated (Testa et al., 2004). This behaviorally specific measure assesses a range of sexual victimization experiences occurring since age 14. A positive response to any item results in being classified as having experienced some type of sexual victimization. Following procedures established by Koss et al. (1987), items were also combined to yield nonmutually exclusive estimates of the proportion of women experiencing unwanted contact due to verbal or physical coercion, verbally coerced sexual intercourse, attempted rape, and completed rape. We also computed a sum of adult sexual victimization experiences. Sexual behavior. A sexual history questionnaire assessed age of first menstrual period and how many sexual partners they had had since menarche using response options 0, 1, 2, 3, 4, 5 9, and 10 or more. For analysis purposes, women who responded 5 9 were recoded as 7 and those who reported 10 or more were recoded as 10. Women who reported ever having sexual intercourse were asked how old they were the first time they had consensual sexual intercourse. They were also asked, On average, would you say that you are most likely to first have sexual intercourse with a new partner..., followed by a list of 6 responses ranging from 1 (on the first day that I meet him) to6(more than a year after meeting him). Responses were recoded so that higher scores indicate more risky behavior. They were also asked, Have you ever had consensual sex with a man that

4 348 TESTA ET AL. you just met that day or evening? with responses ranging from 1 (I have never done this) to8(more than 50 times). Women also indicated whether or not they had ever been told that they had chlamydia, hepatitis B, gonorrhea, genital warts/hpv, genital herpes, trichomonas, or pelvic inflammatory disease. Those who responded positively to any of these were coded as having had a sexually transmitted infection. Finally, women were asked two questions about whether they had ever had sex in exchange for drugs or sex in exchange for money. These responses were combined for analysis. Demographic variables. Demographic variables included date of birth, marital status, and racial/ethnic background. Highest level of education completed was assessed on a 6-point ordinal scale: 1 (less than high school), 2 (high school), 3 (partial college), 4 (college graduate), 5 (some graduate school), 6 (graduate degree). Family income was assessed on an ordinal scale ranging from 1 (less than $10,000) to7($75,000 or more). Women were classified as urban or suburban dwellers based on home ZIP code. RESULTS Willingness to Participate During the CASI recruitment phase, 1,653 eligible women were identified and offered the opportunity to participate in the study. Of these, 1,302 agreed and scheduled an appointment (78.8%). Although most of these women agreed to participate during the initial telephone call, some were unsure and requested more information before deciding. Additional information describing the study and a brochure about the Research Institute were mailed to 346 women. Of these, 172 (49.7%) ultimately agreed to participate, suggesting that sending an informational letter is an effective method for boosting response rate. During the SAQ recruitment phase, 363 eligible women were identified and 349 (96.1%) agreed to participate. The proportion who agreed to complete the SAQ was significantly higher than the proportion who agreed to participate in the CASI, χ 2 (1) = 60.62, p< To encourage a high completion rate in the CASI study, appointments were scheduled at the woman s convenience, reminder phone calls were made before every appointment, and appointments were rescheduled up to three times following no-shows or cancellations. Despite these efforts, of 1,302 who agreed to participate, only 1,017 1 completed the assessment (78.1%). In contrast, a significantly higher proportion of women who agreed to participate in the SAQ assessment actually did complete the study (318/349 or 91.1%), χ 2 (1) = 30.09, p< The majority of completed SAQ booklets (82%) were returned within the 2 weeks in which they were requested. Those who did not return their booklets within 2 weeks received reminder phone calls, which resulted in 95% of completed booklets being returned within 1 month after they were sent. Overall, the completion rate for CASI (completed/identified eligible participants) was 61.4%. The proportion of eligible women who completed the SAQ (87.6%) was significantly higher than the proportion who completed CASI, χ 2 (1) = 90.49, p< Comparison of CASI and SAQ Samples We compared the demographic characteristics of the CASI sample (n = 1,014) with those of the SAQ sample (n = 318). The SAQ sample did not differ significantly from the CASI sample on age (M = years old [SD = 3.78] vs. M = [SD = 3.71]), level of education (M = 3.17 [SD = 1.24] vs. M = 3.18 [SD = 1.13]), family income (M = $42,380 [SD = $23,970] vs. M = $40,125 [SD = $23,039]), or percent currently married (23.3% vs. 20.8%). However, the SAQ sample contained a significantly higher proportion of European American women than the CASI sample (83.9% vs. 75.3%), χ 2 = 10.22, p<.01; a lower proportion of African American women (10.1% vs. 16.9%), χ 2 = 8.56, p<.01; and a lower proportion of city residents (29.2% vs. 37.1%), χ 2 = 6.52, p<.05. Behavioral Self-Reports: CASI vs. SAQ A primary goal of the study was to determine whether selfreported sexual behaviors or sexual victimization experiences differed by mode of questionnaire administration. Raw means or percentages for key variables are displayed for the CASI and SAQ samples in Table 1. Because there were some demographic differences between the CASI and the SAQ samples and these may influence reported behaviors, comparisons were made after controlling for demographic variables. However, the pattern of results is identical when comparisons are made without adjusting for covariates. In general, riskier sexual behaviors and sexual victimization experiences were positively associated with age and urban residence and negatively associated with education. For variables with dichotomous outcomes, we performed logistic regression and report the adjusted odds associated with each sample (1 = CASI, 2 = SAQ) after controlling for age, education, income, marital status, race, and urban dwelling. For continuous outcome measures, we report standardized regression coefficients associated with sample type, after controlling for demographic variables. As shown in Table 1, there were few differences on selfreported consensual and nonconsensual sexual experiences for the two samples. Of the many variables that were compared, significant differences emerged on just three variables. Compared to the CASI sample, the SAQ sample reported having sex with a new partner earlier in the relationship and higher frequency of sex on the same day of meeting a partner. These effect sizes were small, that is, less than one half of a standard deviation. The SAQ sample also was more likely to report experiencing unwanted

5 Impact of Mode on Reporting Sexual Behavior 349 Table 1 Self-Reported Sexual Behavior According to Mode of Administration CASI SAQ Odds Ratio a Sexual Behavior Measures n = 318 n = 1014 β a (95% CI) Age of first menstrual period (1.73) (1.57) 0.01 Number of sexual partners 5.18 (3.54) 4.85 (3.62) 0.03 Age of first consensual sexual intercourse b (2.46) (2.24) 0.02 How soon first intercourse b,c 2.96 (.93) 3.25 (1.02).13 Frequency of intercourse same day met b,c 1.59 (1.03) 1.78 (1.21).07 Sex in exchange for money or drugs b 4.4% 4.0% 1.02 ( ) Lifetime STD infection b 18.4% 18.3% 1.06 ( ) Any childhood sexual abuse (CSA) 32.1% 33.1% 1.13 ( ) Penetrative CSA ( ) Nonpenetrative CSA ( ) Number of CSA experiences 1.01 (1.80).99 (1.70).00 Any adult sexual victimization 38.4% 39.8% 1.04 ( ) Unwanted sexual contact 27.5% 35.0% 1.38 ( ) Verbally coerced intercourse 18.9% 21.5% 1.18 ( ) Attempted rape 12.4% 13.6% 1.13 ( ) Completed rape 17.3% 18.3% 1.04 ( ) Number of adult sexual.95 (1.59) 1.14 (1.83) 0.04 victimization experiences a Adjusted for age, education, marital status, White race, Black race, income, and urban dwelling. b Based on women who reported one or more sexual partners. c Higher values indicate riskier behavior. p<.05. p<.001. sexual contact since age 14 compared to the CASI sample. Unwanted sexual contact is a composite comprising three items: unwanted contact resulting from verbal pressure, physical force, or misuse of authority. Although not shown in the table, we also compared each individual item assessing childhood sexual abuse (8 items) and adult sexual victimization (11 items), controlling for demographics. The only item on which a significant difference emerged was the first SES item, unwanted sexual contact due to verbal pressure, with the SAQ sample more likely to report this experience, OR = 1.43, 95% CI = , p<.05. DISCUSSION Findings did not support the notion that CASI yields higher self-reports of consensual or nonconsensual sexual behavior relative to SAQ among a community sample of women. Although many variables were compared, there were just three modest differences between administration modes. Higher levels of sexual risk behaviors were reported by women who completed SAQ at home compared to CASI at a central location. One explanation for this pattern of findings pertains to the type of questions we asked. Turner and colleagues (1998) found an advantage of CASI over SAQ only for the most sensitive of questions. It is possible that women in this community sample did not find questions on sexual behavior or sexual victimization to be highly threatening. Moreover, the SES was specifically designed to be self-administered and underreporting is thought to be diminished by the use of multiple, behaviorally specific items that do not require the woman to label her experiences as rape or abuse (Koss, 1993). We followed the same principles in our measure of childhood sexual abuse. These questionnaires appear to be well suited to self-administration, with no apparent advantage to CASI. Paper-and-pencil measures of victimization provide, at a glance, information as to the general content that is being assessed. Women may change answers as they go down the list or look at the whole list first before deciding what to answer. Given this possibility, CASI may in fact be a disadvantage because questions appear one by one, and it is difficult to go back and change answers. To change an answer would require alerting the research assistant for help and possibly compromising privacy of responses. Although it may be a spurious finding, CASI resulted in lower reports only on the very first item on the SES (sexual contact due to verbal pressure). Caution is warranted before concluding that CASI administration has no advantage over SAQ for assessment of sexual behaviors, however. The CASI and SAQ conditions were guided by practical concerns and were not completely comparable. The CASI was completed while a research assistant was in the room, and questions regarding sexual experiences were administered following completion of a face-to-face interview involving alcohol use. Although we emphasized the privacy of responses, we cannot rule out the possibility that interaction with an interviewer or her mere presence elicited social desirability concerns in CASI respondents, resulting in a dampening of responses.

6 350 TESTA ET AL. Although reports of sexual behaviors differed little according to mode of administration, there were substantial differences in completion rates according to mode. Unlike studies that randomize participants to mode of administration after they are recruited into the study, women in this study made the decision to participate after learning what type of administration was involved. Although this decision may be viewed as an experimental limitation in that the two samples were not completely equivalent, this methodology was employed deliberately to provide practical information on response rates associated with in-person versus remote data collection. A significantly higher percentage of women were willing to agree to complete the SAQ at home than to complete a CASI that required traveling to a central location. Actual completion rates differed for these two groups as well because a substantial number of women who initially agreed to participate in the CASI failed to keep their appointments despite repeated attempts to reschedule. In particular, White suburban women were more likely to participate in the SAQ compared to the CASI, suggesting that research participation requiring travel to an inner-city location was viewed as particularly burdensome by these women. Because higher response rates typically permit greater confidence when generalizing findings, the significantly higher response rate associated with in-home assessment is important to consider when making decisions about mode of assessment. We acknowledge that the difference in response and completion rates for SAQ versus CASI administration may have been somewhat inflated by the fact that the CASI was described as taking somewhat longer to complete than the SAQ (2 hours vs. 1.5 hours) and including a face-to-face interview component. Although we cannot rule out the possibility that this difference resulted in a systematic volunteer bias, we minimized this confound by describing the study as covering the same content and not telling respondents what the interview component would entail. Another limitation to our design is that assignment to condition took place in two discrete time periods such that CASI participants were recruited prior to SAQ participants. Although unlikely, we cannot rule out the possibility that mode differences in responses or response rates reflect the influence of an event, such as a well-publicized sexual assault case, occurring just before initiation of SAQ recruitment. Nonetheless, the high completion rate for the SAQ (87.6%) among a sample recruited through RDD is quite striking, particularly in an era in which survey response rates have been dropping precipitously (Curtin, Presser, & Singer, 2005). Although mail surveys are often dismissed as yielding low response rates, rates can be substantially elevated with follow-up phone calls reminding participants to return their questionnaires, a procedure which we used in the present study (e.g., Dillman, 1983; Gore-Felton et al., 2002). We believe that initial telephone contact also helped to ensure good response. Our female staff was experienced in telephone recruitment and refusal conversion and were trained to be courteous and reassuring, but also persuasive and persistent. The financial compensation likely also contributed to the excellent response rate, although this should not be overstated. Research indicates that small incentives provided with a survey may boost mail response rates; however, these studies fail to find that an incentive promised upon completion, even as high as $50, improves response rates beyond a no incentive control group (Church, 1993; James & Bolstein, 1992). Although in combination our procedures resulted in a high response rate, the study was not designed to determine which of these components of our procedure were responsible for this rate. The study may be viewed as providing a strong endorsement for using SAQ completed at home for obtaining data about sexual behavior among a community sample of women. That is, women were equally if not more willing to admit to risky sexual behavior via SAQ, and participation rates were higher compared to CASI at a central location. Ultimately, however, making the decision about data collection mode requires consideration of the advantages and disadvantages of each. For example, unlike CASI, at-home SAQ administration does not lend itself to complicated skip and branching patterns and does not permit personal interviewing. For populations likely to have reading difficulties, audio-casi, in which questions are read aloud as well as displayed on screen, may be a better alternative than SAQ completed at home. Moreover, missing data is extremely rare in CASI questionnaires because respondents must either answer a question or provide a refuse response to permit the program to move on to the next question. Missing data is more common on SAQs (Hallfors et al., 2000), and researchers may choose, as we did, to follow up by telephone to obtain answers to key items wherever possible. Finally, SAQ must be checked and data entered before the data are ready for analysis. CASI requires a good deal of programming time to prepare the questionnaire, but data are available immediately. 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