This study of three Internet-based recruitment methods identified a high degree of success at reaching young adults who have smoked cigarettes recently, though costs, participant eligibility, proportion of completed surveys, and respondent characteristics differed among the three methods. Advertisements on Craigslist, a free classified advertisement service, were easy to post and affordable, however, attracted a large proportion of individuals who were ineligible due to age or smoking status. The survey sampling strategy was more successful at targeting eligible survey respondents than the Internet advertising (59% vs. 44% of those who signed online consent) and was also more affordable than advertising through Abrite, especially for completed surveys. SSI did not charge for incomplete surveys. Overall, the Internet advertisement campaign generated the most eligible and enrolled participants; however, the survey sampling method was more affordable and better able to target the population of interest. Online surveys that target young adults anonymously should take into account that while costeffective, it is harder to target young adults directly through Craigslist, and Internet advertising may not be as costeffective as E-mail sampling.
The sample of young adult smokers presented here differed from other samples in a few important ways. The proportion of nondaily smokers in the sample was 32.9%, which is higher than national estimates of nondaily smoking among young adults (24% in 2005; Husten, 2007
). Since nondaily smokers may be less likely to identify as smokers than daily smokers (Husten, McCarty, Giovino, Chrismon, & Zhu, 1999
), it is particularly important that online recruitment strategies targeting young adults take this into account. This sample also was highly motivated to quit, with over half of the young adults recruited reporting that they would be willing to quit smoking in the next 6 months. This number is higher than some other studies that have examined stage of change among young adults (Pallonen, Murray, Schmid, Pirie, & Luepker, 1990
) and suggests that the Internet may be an important mechanism to develop and implement interventions targeted to young adult smokers ready to quit.
Past month alcohol and marijuana use rates in our sample were greater than those reported in other samples of young adult smokers (e.g., Foldes et al., 2010
). Young adult smokers who tend to use multiple substances may be more reachable through the Internet (particularly Craigslist.org
advertising and paid advertising campaigns) compared with more traditional strategies, such as telephone surveys. In addition, those who use illicit substances may feel more comfortable disclosing these behaviors in the context of a confidential Internet survey compared with face-to-face or telephone-based survey methods.
The samples recruited through the three online strategies differed from one another demographically. More women started the survey who were recruited from SSI or Craigslist methods compared with Adbrite advertisements. Studies looking to target a specific gender may have more success with a sampling service (which had more women registered with their service) or the free service Craigslist rather than purchasing Internet advertising. Craigslist attracted an ethnically diverse group of young adult smokers, which is not surprising given that the campaign targeted major metropolitan areas that were more likely to have diverse populations. Since Whites are more likely to be daily Internet users than other ethnic groups (Lenhart et al., 2010
), studies looking to recruit ethnically diverse samples could benefit from making use of Craigslist. There also were education differences such that the sample from Craigslist was somewhat more likely to have completed college or have postgraduate work, while the Internet advertisements appeared to reach out to those who were currently in college.
There were no differences in proportion of respondents who were eligible and began the survey by region of residence. Rates of smoking among young adults in the United States do vary by region. The National Survey of Drug Use and Health indicates that in 2008, prevalence rates of past month cigarette use by region among those aged 18–25 years were 35.0 (Northeast), 40.8 (Midwest), 36.3 (South), and 30.6 (West; Substance Abuse and Mental Health Services Administration, 2009
). The distribution of our sample by region indicates that the Internet-based strategies used to recruit young adults may be particularly successful in the West and relatively less successful in the Midwest.
Compared with Craigslist and Adbrite advertising, the SSI strategy found young adults who demonstrated a slightly heavier smoking pattern (greater nicotine dependence) and slightly lower likelihood of use of other substances. Studies that attempt to target young adults who are heavier smokers (e.g., cessation intervention trials) may be more successful with a sampling strategy than Internet advertising. However, the Internet advertisements (including Craigslist, social networking, and other Web sites) may be useful at surveying young adults about multiple substance use.
This study had some limitations. First, the use of the Internet as a recruitment source limits the pool of individuals to those who have online access (93% of the young adult population), and since frequency of an adult’s internet use is positively correlated with both educational attainment and household income (Lenhart et al., 2010
), samples may not be representative of the entire population of young adult smokers in the United States. Second, the Internet, while particularly useful to those who want an anonymous forum to share information, could pose some challenges to generating valid data. It is important to incorporate methods of validating data collected anonymously online and, if possible, to compare these data with data collected by other methods (e.g., telephone surveys, in-person surveys). As with any Internet-based study, there was also the potential for participants to dropout early. It is important to incorporate strategies to increase the number of completed surveys into the survey design. For example, in the current study, moving the page that requested participants to provide an E-mail address to be notified of drawing results from the end of the survey to the beginning increased completed surveys from 59% to 66%. Comparing strategies to compensate participants for their time (e.g., a chance to win a large prize compared with a guaranteed compensation of lesser value) would have better evaluated whether our strategy was most effective. Finally, the present study was focused only on recruitment of young adults living in the United States. While the exact Web sites, costs, and participant characteristics reported here may be vastly different than those found in other countries, the Internet would likely be a successful recruitment strategy in other countries, and future studies should examine this further.
Overall, our Internet-based recruitment strategy for young adult smokers went quickly and smoothly and was successful in attracting young adults who have had recent cigarette use. Findings suggest that a multipronged approach to Internet recruitment is most likely to generate a broad diverse sample of young adult smokers. Further, the young adults reached through this study were particularly motivated to quit smoking in the future, suggesting that an Internet-based intervention could be particularly useful for this group. Internet-based strategies serve as an important mechanism to reach a widespread diverse group of young adults to understand and eventually reduce smoking behavior.