Data of psychological measures, obtained after opt-in recruitment through Internet sites, were compared to those from the administration of print questionnaires. In the first study, 545 participants from online communities completed the Factorial Scale of Satisfaction in Couple Relationship, the Rusbult Scale of Relationship Satisfaction and the reduced version of the Psychological Well-Being Scales. In the second study, 1,197 participants of websites about soccer answered the Soccer Supporter Team Identification Scale and the Soccer Supporter Fanatism Scale. Factorial structure and reliability results are similar in both versions. However, in the second study, there were differences due to a bias in the sample, pointing out the opt-in strategies limitations.
participant recruitment; Internet; web surveys; research methodology; opt-in sampling
