This has led some to question whether randomised controlled trials are appropriate in palliative care [ 1, 8].
However, although controlled trials are appropriate for establishing potentially causal associations, more naturalistic studies have the advantage of assessing "real life" situations of patients under treatment.
Some clinical heterogeneity was therefore inevitable, even when patients in the trials were similar, with similar conditions, when trial designs included both randomisation and double-blinding, and when the duration of trials was appropriate.
There were only three eligible trials, with five comparisons, in a total of 551 patients, where one biologic therapy (axitinib, cediranib and panitumumab) was compared with different biologic (bevacizumab) added to the same standard treatment, so that the trials were appropriate for comparison.
The study design of a randomized controlled trial is appropriate for the underlying research question.
Given these results and the programme's broad dissemination, testing the programme in a randomised control trial is appropriate.
For the most accurate measurement of overall antibiotic effect on resistance in communities, a cluster-randomized intervention trial is appropriate (45 ).
The retrospective cohort trial is appropriate, but testing stronger strains of C. difficile, using higher-sensitivity detection methods, and tracking the entire length of stay would more accurately support the authors' conclusions.
The initial telephone screening procedure implemented in this trial was appropriate, and only one patient required attendance for further screening before a descision could be made; furthermore only one patient refused consent to participate in the trial.
Data sets drawn from studies that involve an intervention trial are appropriate for this RFA; these proposals should address the approach to handling intervention effects when exploring etiologic questions.
