Outcome reporting bias: cherry-picking the best results When planning an RCT, the choice of primary outcome is crucial. This is an integral part of the research question, and forms the basis of the sample size calculation. Secondary outcomes are also chosen, to give a wider indication of the effects of interventions, generate new hypotheses, and […]
Reading between the lines part 3: Hiding who got what
Performance and detection bias – hiding who got what Bias can occur if the treatment arm to which a given participant is randomized is known. When reading an RCT report, the term “double-blind” is often not sufficient to help appraise this. We need to know from whom treatment identity was masked, and how. […]
Reading between the lines part 2: Some ‘equal groups’ are more equal than others
Selection bias – some ‘equal groups’ are more equal than others The groups of participants receiving interventions should be equal, otherwise confounding variables might give one treatment an advantage over another. If there is a systematic reason for this, the study is at risk of selection bias. Randomization (sequence generation) The first consideration is […]
Clinical trials – reading between the lines.
Another new series of blogs here in the ADC website, from Ian Sinha of the Respiratory Unit, Alder Hey Children’s Hospital, Liverpool, UK, takes a look at explaining the deeper depths of critical appraisal of randomised controlled trials from the perspective of the Cochrane collaboration’s approach to this issue. – Archi Clinical trials – reading between […]