Randomisation assigns study participants to groups by chance. Its purpose is to make a comparison less dependent on who chose a particular group. For a reader, the useful question is how allocation was carried out and reported, rather than whether the word “randomised” appears in a headline.
Start with the comparison
Write down what each group received or experienced and what the researchers measured. A comparison is difficult to interpret if those details are missing. The group names in a results table should be traceable to the methods section; avoid filling gaps from a press release.
Allocation and blinding answer different questions
Allocation concerns how someone enters a group. Blinding concerns who knows the assignment during the study. Record these separately. A randomised study is not necessarily blinded, and an open-label design should not be described as blinded simply because allocation was random.
Follow participants through the report
Compare the numbers assigned, followed up and included in each analysis. When those numbers differ, look for the authors’ explanation. Keep that explanation beside the result in your notes. A short abstract may not contain enough detail to do this, so consult the full paper and any linked supplementary material.
A practical reading note
Use four fields: comparison, allocation method, who was blinded, and which participants contributed to the reported result. Add “not reported” where necessary. This gives another reader something concrete to check without turning the study label into a verdict about a product.
This is an introduction to reading research design, not a protocol for running a clinical trial. It makes no assessment of any listed material or treatment. Keep the paper with your research reading record.
Sources
NCI: randomisation. NCCIH: minimising bias.
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