Try out PMC Labs and tell us what you think. Learn More. New York, NY. We adapted time-space sampling to enroll men who have sex with men MSM off Craigslist. Participants scheduled via online pre-screening were more likely to present for their face-to-face assessment than men deemed eligible directly via phone screening Online pre-screening was a useful tool to offer potential participants when recruiting on Craigslist and improved study enrollment. Online recruitment has become a popular approach to reach large s of people for research on HIV prevention and sexual health [ 1 — 3 ].
Despite the many advantages of using the Internet for collecting data, engaging hard-to-reach individuals, and conducting web-based interventions [ 6 ], only a few studies have reported on using the Internet to recruit MSM for face-to-face assessments [ 1 — 3 ]. Data suggest that it is possible to engage MSM online for subsequent in-person interviews, though with high attrition between first contact and actual assessments.
Parsons et al. Elford et al.
Out of the 1, men who completed online surveys, 93 completed in-person interviews. Craigslist—an online bulletin board—is a medium where users post single through the site, but subsequent correspondence occurs out of the website via private. The site is organized by city and neighborhood such that users can search for and post near their geographic location. are displayed in reverse chronological order newest on top.
Up to ad headlines are displayed on awith older posts in queue on subsequent s. In New York City NYCthe men-seeking-men section is extremely active—one study noted that between two to four thousand were posted every day [ 7 ]. The structure of Craigslist makes its virtual environment different from many traditional membership-based websites.
It does not maintain internal correspondence mechanisms e. Aside from automated filters to prevent duplicate or the inclusion of a telephone or URL, content is not moderated by a central administrator.
Instead, users moderate the site. Any user can flag an ad for removal. However, this procedure excludes individuals who use Craigslist exclusively as browsers i.
Adapting recruitment approaches deed to maximize the representativeness of samples in physical spaces where MSM congregate, might be useful to overcome some sampling bias in recruiting Craigslist users. Our goal was to adapt time-space sampling [ 910 ], a probability-based strategy that utilizes a two-stage process to systematically sample individuals at randomly selected venues and times, to reach sexually active MSM in the NYC metropolitan area via Craigslist.
Time-space sampling has been adapted by the CDC for web-based HIV behavioral surveillance [ 11 ] and for recruitment in Internet chat rooms [ 3 ]. In this study, we report on screening and enrollment outcomes to reach our target sample.
We compared eligibility and participant loss rates based on whether potential participants chose to call our office directly or self-selected to complete the online pre-screener after responding to our study ad. Given that it is largely unknown whether Internet-based samples are representative of the target population and whether they are comparable to samples recruited through other methods [ 11 ], this descriptive study was intended to provide data on online recruitment using an adaption of time-space sampling for in-person interviews in order to inform decisions about sampling and enrollment approaches that target MSM in online environments.
Data are taken from Project Scorea pilot study investigating the places where sexually-active MSM meet their sex partners.
To be eligible, participants had to be biologically male, at least Craigslist men sex Mexico years of age, report at least two new male sex partners within the last 30 days, able to complete an assessment in English, and have a working phone. Those eligible were invited to participate in a face-to-face interview at our research office.
We adopted time-space sampling in order to reduce bias caused by only posting at times that were convenient for the research staff e. Following guidelines for time-space sampling [ 910 ], the research team first identified the most socially-viable times in which to recruit on Craigslist—determined as having an adequate magnitude of the target population at the venue. Based on our experience doing research on Craigslist we determined that the hours between 7am and 2am were the most viable in which to encounter the target population.
We divided these times into one hour increments e. The of postings in a given week was limited to two in order to ensure adequate resources were available to see participants during eventual face-to-face assessments. We weighted borough selection to match NYC census data e. At the date and time selected, a member of the research staff posted an ad for the study in the men-seeking-men M4M section on Craigslist, which is the only section exclusively dedicated for men to seek sex with other men.
Automated filters on Craigslist prevent users from posting a duplicate ad within seven days even if said ad was pulled offline, for example, five days ago. The body text of the were identical and included the study logo, study description i. Automated filters prevented us from including our telephone or URL in the text of the ad. Research staff replied to inquiries promptly. Our messages indicated that they could a call the project directly and screen via phone or b complete a brief online preliminary screener URL included that would ask for their contact information if they appeared eligible and study staff would re-contact them via phone.
Ultimately, all participants had to complete a full screening via phone before they could be scheduled for a face-to-face assessment. It also assessed sexual identity gay, bisexual, heterosexual, other and race or ethnicity, but these were not factored into eligibility. We conducted phone assessments to screen for full eligibility criteria outlined ly in addition to participants self-reported HIV status, race and ethnicity, and the NYC borough in which they lived.
We tracked recruitment efforts in multiple ways.
We recorded the day, time, and NYC borough in which were posted in addition to the of responses we received from each posting. We recorded the of men who telephoned us directly versus those who opted to first complete the brief screening survey online.
We compared eligibility and participant loss rates based on whether potential participants chose to call our office directly or self-selected to complete the online screener first. Between August and Marchour research team posted to Craigslist 36 times. Three of our were flagged and removed by the Craigslist community before we received any responses an ad posted in Manhattan, Staten Island, and the Bronx. Of the 28 that were never flagged, we received an average of 11 s per ad range 0 to Across all postings, there were no ificant differences in the mean of s received by 1 the borough where were posted, 2 the time of day that were posted morning vs.
In total, we received unique replies to our postings. Project staff responded to every directing participants to either call our center directly or complete a brief online screener. Figure 1 displays the paths individuals self-selected during this recruitment process.
Forty-one men There were three additional men 0. None of these three participants were eligible for the study. Comparing retention of participants who opted to telephone us directly versus those who first completed a survey online.
Of the seven men who telephoned us directly and were not eligible, six reported an insufficient of new male partners in the last 30 days. All men who did not meet preliminary criteria were excluded solely because they reported an insufficient of new male partners in the last 30 days.
Among those who we ultimately reached via phone, participants deemed eligible via the online pre-screening route were ificantly more likely to show for their face-to-face assessment than men deemed eligible directly via phone screening Three participants did not report their borough. We adapted time-space sampling for use in the men-seeking-men section of Craigslist.
Our goal was to determine if men who elected to first complete an online pre-screener were more likely to show for a face-to-face assessment, compared to men who elected to call our office and screen via phone directly. Although the online pre-screener route ultimately involved more steps, we believe it was a less socially invasive approach for participants—it is easier to complete a confidential online survey than to speak with a stranger on the phone.
We believe this is why a larger proportion opted for the online pre-screener.
More than double the of men self-selected to complete the online pre-screener and, from this pool of potential participants, a ificantly higher proportion of those who our staff were able to schedule via phone ultimately showed for their face-to-face assessment. These findings suggest online pre-screening is a useful tool to offer potential participants when recruiting in a virtual environment.
This approach suggests that participants who first complete a brief research study component are more likely than others to participate in a more intensive research component.
In turn, this may improve overall external validity. Our findings, however, should be understood in light of several limitations.
Craigslist also maintains other listings e. Although we have data on the of potential participants who responded via to our ad on Craigslist, we do not know how many men viewed our ad. Craigslist has automated filters preventing inclusion of a phone or URL as text ; however, it is possible to embed this information as part of a photo i.
Craigslist is moderated by its users and our posts were not necessarily germane to the bulletin board i. Some of our were flagged for removal by the Craigslist community, particularly those posted in the borough of Queens. Further, although we adapted time-space sampling to maximize exposure of ourthe physical location of our office in Manhattan may have precluded some participants in other boroughs from participating.
We noted high attrition in our efforts to reach MSM online for face-to-face assessments; however, this appears to be common across studies and with a wide range of variability. Similarly, Fernandez et al.
However, given that recruitment often takes place in steps, there are many places where attrition can occur. For example, more than half of the men who responded to our via never took further initiative to the study. We do not have data on these men, but suspect that upon learning more i.
Project staff reached out to these men multiple times to reschedule.
More often than not, these calls went directly to voic and our s were not returned. We do not have sufficient tracking data on men who did not show to determine if there were differential reasons for no-show based on whether men self-selected to complete the online survey first or called us directly. Participants were recruited using an adapted method of time-space sampling. An advantage of time-space sampling is its systematic approach for capturing location-based populations; however, it has the potential to oversample those who frequent venues of recruitment.
Traditionally, time-space sampling involves actively approaching participants e. This allowed us to reach a broader population of the Craigslist community, by including men who browse through but may have not posted one themselves [ 7 ]. Future research should investigate if active versus passive approaches online result in different response rates and sample characteristics. Our randomization schema was determined in part based on resources available to see participants during face-to-face assessments we limited randomization to two postings a week.