Risk of selection bias in randomised trials
نویسندگان
چکیده
منابع مشابه
Risk of selection bias in randomised trials
BACKGROUND Selection bias occurs when recruiters selectively enrol patients into the trial based on what the next treatment allocation is likely to be. This can occur even if appropriate allocation concealment is used if recruiters can guess the next treatment assignment with some degree of accuracy. This typically occurs in unblinded trials when restricted randomisation is implemented to force...
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Factorial trials are an efficient method of assessing multiple treatments in a single trial, saving both time and resources. However, they rely on the assumption of no interaction between treatment arms. Ignoring the possibility of an interaction in the analysis can lead to bias and potentially misleading conclusions. Therefore, it is often recommended that the size of the interaction be assess...
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The quality of randomization is an under-appreciated facet of trial design. The present piece represents an advance in our collective understanding of how allocation concealment and randomization relate to risk of selection bias in randomized trials, and other measures are also considered. Though the overwhelming majority of the advice given is timely and correct, it is more instructive to focu...
متن کاملPreventing Bias in Cluster Randomised Trials
In randomised trials, internal validity is defined as ‘‘the extent to which the design and conduct of a study are likely to have prevented bias’’ [1,2]. In conducting such trials, trialists try to prevent selection bias through randomisation and allocation concealment (defined as ‘‘the process used to ensure that the person deciding to enter a participant into a randomised controlled trial does...
متن کاملMethodological bias in cluster randomised trials
BACKGROUND Cluster randomised trials can be susceptible to a range of methodological problems. These problems are not commonly recognised by many researchers. In this paper we discuss the issues that can lead to bias in cluster trials. METHODS We used a sample of cluster randomised trials from a recent review and from a systematic review of hip protectors. We compared the mean age of particip...
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ژورنال
عنوان ژورنال: Trials
سال: 2015
ISSN: 1745-6215
DOI: 10.1186/s13063-015-0920-x