Article type
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Abstract
Background: Meta-analyses of continuous outcomes typically provide enough information for decision makers to evaluate the extent to which chance can explain apparent differences between interventions. The interpretation of the magnitude of these differences - from trivial to large - can, however, be challenging.
Objectives: To investigate clinicians’ understanding and perceptions of usefulness of six statistical formats for presenting continuous outcomes from meta-analyses: standardized mean difference (SMD), minimal important difference units (MID), mean difference (MD), ratio of means (RoM), relative risk (RR), and risk difference (RD).
Methods: We invited 610 staff and trainees in family medicine and internal medicine programs in eight countries (Europe, North and South America, and the Middle East) to participate. Paper-based, self-administered questionnaires presented summary estimates of hypothetical interventions versus placebo for chronic pain. The estimates were either for a small or large effect for each of the six presentation approaches. Questions addressed participants’ understanding of the magnitude of treatment effects and their perception of usefulness of the format. We randomized participants to size of effect and order of presentation of the different formats.
Results: 531 (87%) of clinicians responded (Table 1). Clinicians best understood RD, followed by the RR and RoM (Figure 1). Similarly, clinicians perceived dichotomous presentation of continuous outcomes (RD; RR) most useful (Figure 2). Compared to family medicine, internal medicine had better understanding and reported higher perceived usefulness of the various presentation formats (P value < 0.005; Figure 3).
Conclusions: No format was very well understood or perceived as extremely useful. Clinicians best understood continuous outcomes when presented as dichotomies (relative and absolute risk differences) and perceived these presentations to be the most useful. Presenting results as SMD, the longest standing and most widely used approach, was poorly understood and perceived as least useful. Further efforts in medical education regarding understanding research results are necessary.
Objectives: To investigate clinicians’ understanding and perceptions of usefulness of six statistical formats for presenting continuous outcomes from meta-analyses: standardized mean difference (SMD), minimal important difference units (MID), mean difference (MD), ratio of means (RoM), relative risk (RR), and risk difference (RD).
Methods: We invited 610 staff and trainees in family medicine and internal medicine programs in eight countries (Europe, North and South America, and the Middle East) to participate. Paper-based, self-administered questionnaires presented summary estimates of hypothetical interventions versus placebo for chronic pain. The estimates were either for a small or large effect for each of the six presentation approaches. Questions addressed participants’ understanding of the magnitude of treatment effects and their perception of usefulness of the format. We randomized participants to size of effect and order of presentation of the different formats.
Results: 531 (87%) of clinicians responded (Table 1). Clinicians best understood RD, followed by the RR and RoM (Figure 1). Similarly, clinicians perceived dichotomous presentation of continuous outcomes (RD; RR) most useful (Figure 2). Compared to family medicine, internal medicine had better understanding and reported higher perceived usefulness of the various presentation formats (P value < 0.005; Figure 3).
Conclusions: No format was very well understood or perceived as extremely useful. Clinicians best understood continuous outcomes when presented as dichotomies (relative and absolute risk differences) and perceived these presentations to be the most useful. Presenting results as SMD, the longest standing and most widely used approach, was poorly understood and perceived as least useful. Further efforts in medical education regarding understanding research results are necessary.