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Using scratch card technology for random allocation concealment in a clinical trial with a crossover design
Mags E Beksinska1, Carol Joanis, Jenni A Smit
1MatCH Maternal, Adolescent and Child Health, Department of Obstetrics and Gynaecology, Faculty of Health Sciences, University of the Witwatersrand, Durban 4091, South Africa. mbeksinska@match.org.za
Clinical Trials (London, England)
|November 29, 2012
Summary
A novel scratch card system effectively conceals random allocation sequences in crossover trials. This method, preferred by staff over traditional envelopes, reduces selection bias in clinical research.
Area of Science:
- Clinical Trials Methodology
- Biostatistics
- Public Health Research
Background:
- Random allocation concealment is vital in clinical trials to prevent selection bias.
- Ensuring participants and researchers are unaware of assignments maintains trial integrity.
Purpose of the Study:
- To develop and assess a novel allocation concealment method for randomized, open-label, crossover trials.
- The method aimed to minimize selection bias in a trial evaluating four female condom types.
Main Methods:
- A scratch card system using concealed foil squares was designed for allocation concealment.
- Treatment sequences were printed on single cards, revealed by scratching foil for each study period.
- Staff in South Africa and China were trained; their experiences were documented via questionnaire.
Main Results:
- Research staff found the scratch card system easy to use, rating it superior to the SNOSE system.
- Common methods for foil removal included coins and fingernails.
- No allocation sequence errors were detected during study monitoring in either trial site.
Conclusions:
- The scratch card system is an effective and well-liked method for concealing consecutive allocations in crossover trials.
- This approach simplifies allocation concealment by using a single card per participant.
- The method is adaptable for various clinical trials and randomized studies beyond female condom evaluations.
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