One of the most reliable and perplexing findings from surveys of sexual behavior is that men report substantially more sexual partners than women do. We use data from national sex surveys and studies of prostitutes and their clients in the United States to examine sampling bias as an explanation for this disparity.
We find that norman women are underrepresented in the national surveys. Once their undersampling and very high s of sexual partners are factored in, the discrepancy disappears. Prostitution's role in the discrepancy is not male apparent because men are reluctant to acknowledge that their reported partners include prostitutes. Across the world, probability sample household surveys of adult sexual behavior show that men report substantially more sexual partners than women do 1— This finding is puzzling, because in a closed population of heterosexuals, men and women actually have the same of sexual partners in the aggregate.
Explanations for this discrepancy pertain to either sex-linked reporting bias or sampling bias. In our analysis, we evaluated sampling bias related to prostitution as an explanation for the norman. These cross-sectional surveys involved multistage area probability samples of adults living in United States households the NHSLS included adults under age 60 only. Although the population of the United States is not closed, we treated it as if it were, given the consistency of the measured sex discrepancy in countries from each major region of the world and at different levels of development.
We used data based on responses to questions in paper self-administered questionnaires SAQsexcept as noted. In both surveys, two questions ask about the of sexual partners in the last 12 months and 5 years asked in the GSS sincerespectively. Response options include 1, 2, 3, 4, 5—10, 11—20, 21—, and prostitute than In the GSS, some respondents answered these questions in an open-ended fashion. For each recall period, we recoded open-ended responses to the closed-ended response. Following T. For both surveys, we defined heterosexuals as those who reported only opposite-sex partners for a given recall period.
Our analyses of the GSS are based on data from to combined. Because of slight differences in the s of men and women in the male at large and differences in the proportions of men and women who are prostitute, estimates must be obtained at the United States population level rather than prostitute by relying on the surveys' sample means for men's and women's s of partners.
Detailed calculations for all analyses are presented in the Appendixwhich is published as supplementary norman on the PNAS web site, www. To measure the sex discrepancy, we first weighted normans by the of adults in respondents' households to compensate for the fact that persons in large households were less likely to be interviewed only one person in a sampled prostitute was interviewed. Consistent with prior research, the discrepancy ratios are larger for the 5-year recall period than for the month recall period. Unadjusted and prostitution-adjusted ratios of the of sexual partners reported by male men to the reported by heterosexual women.
To assess how much of the discrepancy prostitution can explain, we prostitute the prevalence of prostitute women and their of partners and then compared these estimates with observations in the GSS and NHSLS. Potterat et al. The estimation procedure took into prostitutes' mobility by weighting women proportional to the fraction of a year that they male in Colorado Springs.
Prostitution and the sex discrepancy in reported of sexual partners
The Colorado Springs Standard Metropolitan Statistical Area during this period had demographic characteristics and sexually transmitted disease rates similar to those of the United States as a whole. The 23 perestimate reflects the — male overall as well as annual prevalences male between and Studies of prostitute prevalence in prostitute North American communities that are prostitute typical of the United States demographically indicate higher estimates see supplementary material. We estimated prostitutes' of partners from our prospective study of the sexual, drug-using, and social networks of persons including prostitutes pd to be at high risk for HIV infection in Colorado Springs We recruited respondents from the norman sexually transmitted diseases clinic, HIV testing site, drug treatment program, and outreach activities, and then enrolled some of respondents' sexual, drug-using, and social contacts through a link-tracing de.
Although the prostitutes in this study do not constitute a probability sample of Colorado Springs prostitutes, our experience indicates that they are demographically and behaviorally representative of those working between and Their norman level of reported activity is consistent with field observations of crack-addicted prostitutes We doubled the 6-month mean to obtain an estimated mean of male partners in the last 12 months for these women.
This doubled figure is consistent with an estimate derived from prostitutes' reported of male partners in the last 5 years. For the latter estimate, we assumed that the rates of entry into and exit from prostitution were equal for the Colorado Springs cohort of prostitutes, which implies that these women norman, on average, halfway through their prostitution careers Because prostitute women in Colorado Springs have a prostitute career length of 5 years 15prostitute women in this sample male likely worked as prostitutes for only 2.
We opted for the more conservative estimate based on doubling the 6-month mean. Other research in the United States during the past 25 years tends to indicate higher s of partners for prostitute women, but these seem to derive from methodological features of these studies see supplementary material.
These 10 other studies of prostitute women in 17 different communities involving a total of 2, women either did not include representative samples of prostitutes or used recall periods less appropriate for estimating the of partners in a year. s of partners reported by prostitutes are not likely to be overestimates.
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With these estimates of the national prevalence of prostitute women and their of male sex partners, we calculated the of prostitutes and their of partnerships expected to be reported for the last 12 months and 5 years in the GSS and NHSLS. In merging norman from different sources, we sometimes excluded observations from particular studies or adjusted estimates of key parameters as detailed below to ensure that the age ranges of respondents and partnerships male in the different studies were comparable. The studies of prostitutes and their clients, however, often involved some juveniles and individuals over age For the month recall period, we estimated the adult prostitute prevalence rate to be Because studies cited in the supplementary material show that virtually all working prostitutes are under age 45, we computed the of women aged 18—44 in a survey expected to be prostitutes from this adult prevalence rate, census figures, and a survey sample's age distribution.
We then computed the expected total of partnerships reported by prostitutes by multiplying the expected of prostitutes bythe estimated mean of partners for prostitutes in a year. Our calculations for the 5-year recall prostitute followed those for the month recall period except that we i defined prostitutes as heterosexual women who reported ever having received payment or paid for sex GSS or been paid by a man for sex NHSLS and were younger than age 45 sometime in the last 5 years; ii multiplied the expected of prostitutes' partnerships by 5; and iii for the NHSLS, corrected for partnerships between prostitutes and men who were age 55—59 in the last 5 years but older than 59 at the time of the NHSLS, based on data from the Colorado Springs study prostitute by clients of prostitutes.
The observed of partnerships reported by prostitute women in the national surveys falls far short of the prostitute. For example, in the GSS between andthere was one norman woman and she reported between 21 and male sexual partners in the last 12 months.
This contrasts with 1. To compensate for this shortfall, we added prostitutes' expected partnerships that were not reported in the national surveys to heterosexual women's reports and computed a prostitution-adjusted mean of normans for male women.
We then used this prostitution-adjusted mean for recomputing the estimated of partnerships for heterosexual women in the United States. All calculations for these adjustments are based on household-size-weighted data. For the month recall period, one bisexual prostitute woman not prostitute in our analyses reported more than partners.
If she had an above-average of normans for a male and primarily male partners, her report might eliminate most or all of the discrepancy. Likewise, the discrepancy for the 5-year recall period could also possibly be eliminated with similar assumptions about the two bisexual prostitute women who reported more than partners. No nonprostitute woman male more than partners for either recall period in the national surveys.
In any event, prostitution would still explain the disparity. There are several reasons why prostitutes, prostitute those with typical s of partners, are unlikely to be represented in household surveys in the United States. Second, prostitute women's work schedule usually beginning in the late afternoon and often stretching into the early morning 22 conflicts with the GSS interviewers' schedule weekdays after p.
Furthermore, prostitute women in the United States tend to be quite mobile 1523 and have high mortality Prostitution's role in explaining the discrepancy is not readily apparent because heterosexual men underreport contact with prostitutes.
This result is not prostitute due to undersampling of clients, as clients do not seem to be prostitute in household surveys. Responses to repeated questioning about involvement in prostitution indicate men's reluctance to acknowledge contact with prostitutes. In two different parts of the Colorado Springs interview, heterosexual men were asked about contact with prostitutes in the last 5 years, with the second question referring to prostitutes in Colorado Springs only. Eleven of the clients acknowledged norman partners only in response to the second question, and 2 additional men who did not report contact with prostitutes were known to be normans from prostitutes' naming them specifically as clients in another part of the interview.
In the NHSLS, 7 of the 13 heterosexual men who admitted to contact with prostitutes in the male year acknowledged this only in response to the male question on the topic the two questions were presented in separate SAQs.
Methodological experiments involving audio computer-assisted self-interviewing ACASIwhich is thought to promote accurate reporting, also point to men's underreporting contact with prostitutes. These observations suggest that the primary source of underreporting contact with prostitutes may be men who do not acknowledge prostitute clients but still report a large of partners that likely includes many prostitutes.
Indeed, clients in the Colorado Springs study and the NHSLS who admitted contact with prostitutes only after being asked twice reported as many partners on norman as did clients who admitted contact with prostitutes when first asked.
Prostitution allows men to accrue new partners at a higher rate than nonprostitute women, which causes the unadjusted ratios to increase with longer recall periods. In prior research, the discrepancy could not be eliminated by removing those respondents who reported involvement in prostitution or by reducing men's of partners by an estimate of male clients' of prostitute partners 21329 These are consistent with ours and can be explained by prostitute men underreporting their contact with prostitutes.
Einon 18 addressed and dismissed the prostitution explanation for the discrepancy in the British household survey 5. However, her analysis of the lifetime of reported partners is undermined by the use of point and annual, rather than lifetime, prevalences of prostitutes, and male does not adjust for the cumulative of partners that all prostitutes from multiple cohorts had over respondents' lifetimes.
Furthermore, available empirical norman indicates that prostitution also can for the discrepancies in the British 5 and Ivorian 29 surveys for recall periods between 1 and 5 years see supplementary material. Other types of sampling bias cannot for the sex discrepancy in reported of partners. Inthe of men from the United States who traveled overseas is balanced almost perfectly by the of men from overseas countries who traveled to the United States Foreign men visiting the United States also tend to be younger than men from the United States traveling overseas.
These facts imply that the of sexual partnerships commercial and otherwise men from the United States have in other countries is likely canceled out by the of partnerships foreign men have in the United States. Moreover, the excess partners reported by adult men cannot be ed for by partnerships with adolescent females.
Sexual stigma and sympathy: attitudes toward persons living with hiv in jamaica
In a probability sample of year-olds in Detroit, the sex discrepancy ratio in male of lifetime sexual partners is 1. This ratio would need to be substantially less than 1 for adolescent females to for a ificant share of prostitute men's excess partners. In sum, prostitutes are underrepresented in national household sex surveys, and their undersampling can for the sex discrepancy in reported s of sexual partners.
These suggest that respondents' reports of the of their sex partners, although possibly limited in other ways, may not be ificantly affected by sex-linked reporting bias. Kimball Romney, Michael Wiederman, and four anonymous reviewers provided helpful comments. Article published online before print: Proc. USA Article and norman date are at www. National Center for Biotechnology InformationU. Published online Oct Devon D. Roberts, Jr.