Their study demonstrates the importance of proper controls to limit the use of unique IDs to one person; implementing such controls is relatively easy in a web-based survey environment.Though unaddressed by Wejnert and Heckathorn due to the nature of their study, web RDS poses an additional complicating feature with hidden populations, particularly those who are security conscientious—that of pro-viding anonymous financial incentives . Bauermeister et al. confront this by issuing “Visa e-gift” cards via email to respondents upon completion of their initial survey and reloading them after their chain referred recruits complete the survey . This appears to be one of the more secure options available to researchers, but it does not fully protect participants in the case of compelled disclosure , as the original “loading” of the cards is linked to researchers and recipients are required to provide a name and address before using the cards. Such a disclosure may seem like a minor consideration when studying use prevalence of multiple drugs in a large sample, but the issue is much more salient as sensitivity and security concerns become more of an issue—as is the case with drug producers or sellers.
Limiting or completely eliminating monetary incentives to participants is one method of maintaining anonymity; however, no one has attempted a RDS study of this nature. This study, in addition to investigating marijuana users in Oregon, attempts the first non-monetary primary incentive RDS implementation. To answer the research questions posed in this study, I developed a web RDS protocol and web-based survey to examine a sample of marijuana users in Oregon. To investigate the role of different secondary incentive types in the success of RDS studies and to protect respondents’ anonymity, I chose to forego all monetary payments. Instead, mobile vertical rack multiple non-monetary secondary incentives were implemented: 1) prospective respondents were ap-pealed to based on the potential political and economic importance of examining their population; 2) live updates and total network referral counts for each respondent were posted on a web site to encourage competition among participants to recruit others; and 3) respondents were granted access to near-live aggregate data and summary statistics as the project developed. Respondents were eligible to participate if they were Oregon residents, over the age of 18, used marijuana in the last year, and received a unique study ID from a previous participant in the study. The web-based survey instrument included a question that tracked study IDs; any previously used IDs were barred from reuse. After completing the survey, respondents were redirected to another web page with instructions about the referral process, as well as links to five additional recruitment letters that could be downloaded and shared with prospective recruits by email, Facebook, or instant message.I identified a single “super seed” with a very large number of friends who are users, producers, and sellers of marijuana in several counties identified in my parallel research study as “areas of interest” within Oregon .
The super seed was fully briefed on the project, the referral process, and the importance of collecting chain referrals by following up with prospective respondents.However, the lack of monetary incentives and the format of the recruitment letters appear to have quickly affected recruitment rates com-pared to previous RDS studies , as the referral process died out with only 72 respondents . The implications of this finding are discussed later. The survey instrument collected self-reported information on: 1) individual characteristics, such as gender, age, height, weight, frequency of exercise, county of residence, ethnicity, political party membership, education level, employment status, relationship status, occupational category, health insurance coverage, number of close friends, and income; 2) marijuana-related questions, including frequency of use, reasons for use, medical license status and roles, number of close friends who use, reasons for growing, number of plants growing, method of growing, source and reimbursement rate for obtained marijuana, amount consumed, and the perceived acceptance of marijuana use by immediate social circle and local community; and 3) a detailed political orientation index .Variables of interest for hypothesis testing in this analysis include frequency of marijuana use, amount of marijuana used per month, number of close friends who use marijuana, perceived peer-group acceptance of marijuana use, use status , level of education, relationship status, number of children, and reasons for using marijuana.The number of close friends who use marijuana is a ratio measure, with a minimum of zero and maximum of 20.