8% (n = 76) met criteria to complete the survey and 88.2% of those (n = 67) completed the survey. Of the 128 individuals who reported learning about the study through Craigslist, 46.9% (n = 60) met criteria, and of those who met criteria, 72% (n = 43) completed the survey. Thus, while Internet selleck chemicals llc advertisements yielded the largest proportion of recruited participants and completed surveys overall, Craigslist and SSI were more successful at targeting young adult smokers who went on to complete the survey. Table 1. Participants by recruitment method Validity of cases Of the 66 original IP addresses that found the survey through Craigslist and met criteria for participation in the survey, 6 (9.1%) were deemed invalid due to inconsistencies in data (e.g.

, reported different birthdates, answered tobacco, or other substance use questions inconsistently). Of the 204 IP addresses from an Adbrite advertisement that met criteria for participation in the survey, 4 (2%) were found to be invalid, and of the 77 IP addresses that found the survey through SSI and met criteria for participation, only 1 (1.3%) was found to be invalid. Costs Advertisements on Craigslist were free to post and, once created, incurred about 5 min of staff time to post online weekly. For the present study, the cost for this mechanism averaged out to $4 per week total, which was $0.66 per eligible participant. For the Internet advertisement campaign, the total budget over 6 months was $5,000. The average cost per eligible participant who began the survey was $20.86: $19.98 for banner advertisements and $22.

61 for text advertisements. The cost per eligible participant to complete the survey was $42.77. For the survey sampling campaign, costs were incurred only for completed surveys and were $19.24 per participant. Considering compensation for participants�� time, the total amount spent on prizes was $2,625 for 30 prizes. The average cost of compensation per completed participant was $13.06 and per participant who began the survey was $7.81. Internet advertisement types In our Internet marketing campaign, there were two banner advertisements and one text advertisement consistently running for 6 months. The two banner advertisements made 3,410,523 impressions, resulting in 2,885 clicks, and 160 eligible participants (5.5%). The text advertisement made 15,788,440 impressions resulting in 1,539 clicks and 80 eligible participants (5.

2%). Dacomitinib Banner advertisements were more successful at generating both interested (63% of enrolled participants vs. 37%) and eligible (59% vs. 31%) participants to the survey. Internet Web sites that were the most successful at generating eligible participants were Facebook (7.4% of enrolled participants), MySpace (10.8%), other social networking Web sites (31.4%), Google (5.3%), and other lifestyle-based Web sites (44.1%), including filesharing (17.2%), entertainment streaming (e.g., YouTube, online radio, podcast; 13.