Inadequate pre-specification of the statistical analysis

Inadequate pre-specification of the statistical analysis The credibility of the results from a randomized trial depends strongly on the quality of the trial’s study design, endpoint definitions, and statistical analysis. Pre-specification in a study protocol (and in a public trial register) is crucial. Without this, endpoints and analyses can be modified, using random variation in… Continue reading Inadequate pre-specification of the statistical analysis

HARKing

HARKing It is quite easy to get a manuscript accepted in a scientific journal if only a few basic requirements are met, i.e. a reasonably interesting research question, a sound study design, and generally acceptable results. Unfortunately, the chance of succeeding with this in a randomised trial is not great. Randomised trials are expensive, time-consuming,… Continue reading HARKing

Experimental and observational studies

Experimental and observational studies The statistical analysis of a dataset is always dependent on how the data have been collected. An experimental study, e.g. a randomised clinical trial, can be designed in such a way that validity problems (selection bias, misclassification bias, confounding bias) are prevented, for example using concealed treatment allocation, randomisation of patients… Continue reading Experimental and observational studies