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Table 1 Key differences between trials with explanatory and pragmatic attitudes (from Zwarenstein et al. [48]).

From: Making trials matter: pragmatic and explanatory trials and the problem of applicability

  Explanatory attitude Pragmatic attitude
Question Efficacy: can the intervention work? Effectiveness: does the intervention work when used in normal practice?
Setting Well resourced, 'ideal' setting Normal practice
Participants Highly selected; poorly adherent participants and those with conditions which might dilute the effect are often excluded Little or no selection beyond the clinical indication of interest
Intervention Strictly enforced and adherence is monitored closely Applied flexibly as it would be in normal practice
Outcomes Often short-term surrogates, or process measures Directly relevant to participants, funders, communities and healthcare practitioners
Relevance to practice Indirect: little effort is made to match the design of the trial to the decision making needs of those in the usual setting in which the intervention will be implemented Direct: the trial is designed to meet the needs of those making decisions about treatment options in the setting in which the intervention will be implemented