3 years ago

Generalisability of an online randomised controlled trial: an empirical analysis

Background

Investigators increasingly use online methods to recruit participants for randomised controlled trials (RCTs). However, the extent to which participants recruited online represent populations of interest is unknown. We evaluated how generalisable an online RCT sample is to men who have sex with men in China.

Methods

Inverse probability of sampling weights (IPSW) and the G-formula were used to examine the generalisability of an online RCT using model-based approaches. Online RCT data and national cross-sectional study data from China were analysed to illustrate the process of quantitatively assessing generalisability. The RCT (identifier NCT02248558) randomly assigned participants to a crowdsourced or health marketing video for promotion of HIV testing. The primary outcome was self-reported HIV testing within 4 weeks, with a non-inferiority margin of –3%.

Results

In the original online RCT analysis, the estimated difference in proportions of HIV tested between the two arms (crowdsourcing and health marketing) was 2.1% (95% CI, –5.4% to 9.7%). The hypothesis that the crowdsourced video was not inferior to the health marketing video to promote HIV testing was not demonstrated. The IPSW and G-formula estimated differences were –2.6% (95% CI, –14.2 to 8.9) and 2.7% (95% CI, –10.7 to 16.2), with both approaches also not establishing non-inferiority.

Conclusions

Conducting generalisability analysis of an online RCT is feasible. Examining the generalisability of online RCTs is an important step before an intervention is scaled up.

Trial registration number

NCT02248558.

Publisher URL: http://jech.bmj.com/cgi/content/short/72/2/173

DOI: 10.1136/jech-2017-209976

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.