How different online recruitment methods impact on recruitment rates for the web-based coortesnaweb project: a randomised trial.

BACKGROUND: The number of web-based E-epidemiologic studies using online recruitment methods is increasing. However, the optimal online recruitment method in terms of maximizing recruitment rates is still unknown. Our aim was to compare the recruitment rates of three online recruitment methods and to describe how these rates differ according to individual's socioeconomic and demographic factors. METHODS: A total of 2394 members of the 1993 Pelotas birth cohort that provided an e-mail address, a Facebook name, and a WhatsApp number during a face-to-face follow-up were randomly allocated to be recruited by e-mail, Facebook or WhatsApp (798 individuals per method). This was a parallel randomised trial applying a block randomisation (block size = 3). Between January and February 2018, we sent messages inviting them to register into the web-based coortesnaweb platform. Recruitment rates were calculated for each method, and stratified according to the individual's socioeconomic and demographic characteristics. We also analysed absolute and relative inequalities on recruitment according to schooling and socioeconomic position. RESULTS: Out of the 2394 individuals analysed, 642 registered into the platform. The overall recruitment rate was 26.8%. Recruitment rates for women were almost 10 percentage points higher compared to men. Facebook was the most effective recruitment method, as 30.6% of those invited through the social network were recruited. Recruitment rates of e-mail and WhatsApp were similar (recruitment rate = 24.9%). E-mail and Facebook were the most effective recruitment methods to invite highly educated and wealthier individuals. However, sending e-mails to recruit individuals also reflected in the highest inequalities according to schooling and socioeconomic position. In contrast, the lowest inequalities according to socioeconomic position were observed using Facebook. CONCLUSIONS: Facebook was the most effective online recruitment method, also achieving the most equitable sample in terms of schooling and socioeconomic position. The effectiveness of online recruitment methods depends on the characteristics of the sample. It is important to know the profile of the target sample in order to decide which online recruitment method to use. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials, identifier: RBR-3dv7gc , retrospectively registered in 10 April 2018.

Response rate differences between web and alternative data collection methods for public health research: a systematic review of the literature.

OBJECTIVES: To systematically review the literature and compare response rates (RRs) of web surveys to alternative data collection methods in the context of epidemiologic and public health studies. METHODS: We reviewed the literature using PubMed, LILACS, SciELO, WebSM, and Google Scholar databases. We selected epidemiologic and public health studies that considered the general population and used two parallel data collection methods, being one web-based. RR differences were analyzed using two-sample test of proportions, and pooled using random effects. We investigated agreement using Bland-and-Altman, and correlation using Pearson's coefficient. RESULTS: We selected 19 studies (nine randomized trials). The RR of the web-based data collection was 12.9 percentage points (p.p.) lower (95% CI = - 19.0, - 6.8) than the alternative methods, and 15.7 p.p. lower (95% CI = - 24.2, - 7.3) considering only randomized trials. Monetary incentives did not reduce the RR differences. A strong positive correlation (r = 0.83) between the RRs was observed. CONCLUSIONS: Web-based data collection present lower RRs compared to alternative methods. However, it is not recommended to interpret this as a meta-analytical evidence due to the high heterogeneity of the studies.

Influência do recrutamento de participantes em sítios temáticos e comunidades virtuais nos resultados de medidas psicológicas aplicadas pela Internet / Influence of participant recruitment in thematic sites and virtual communities on the results of psychological measures applied through the Internet

Foram comparados os resultados de medidas psicológicas obtidos após recrutamento opt-in em sítios da Internet com os resultados de aplicações de questionários impressos. Em um primeiro estudo, 545 participantes de comunidades online completaram a Escala Fatorial de Satisfação em Relacionamento de Casal, a Escala Rusbult de Satisfação no Relacionamento e uma versão reduzida das Escalas de Bem-Estar Psicológico. Em um segundo estudo, 1.197 participantes de sítios sobre futebol responderam à Escala de Identificação do Torcedor com o Time e a Escala de Fanatismo em Torcedores de Futebol. Os resultados de estrutura fatorial e confiabilidade são semelhantes em ambas as versões. Porém, no segundo estudo, houve diferenças devidas a um viés da amostra propiciado pelo tipo de coleta, indicando limitações da estratégia opt-in.

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.