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Table 2 Advantages and disadvantages of selecting a broad versus narrow research question for a systematic review of adverse effect

From: Systematic reviews of adverse effects: framework for a structured approach

Scope Pros Cons
Narrowly focused, usually evaluating only a selected adverse outcome in detail. Example: Does antidepressant X increase the risk of suicides in teenagers? Easiest approach, especially with regard to data extraction. Hypothesis-testing design allows reviews to focus on important adverse effects and reach conclusions about treatment decision [3] Conclusions are limited to specific adverse effects, and do not provide a complete picture of the overall safety or tolerability profile. Method is appropriate only for adverse events known in advance
Broad sweep. Example: What common adverse effects might a patient experience when starting on a tricyclic antidepressant? This method can evaluate new adverse effects that were previously unrecognized, and will provide a broad general view of potential problems. Can also be used as part of a scoping exercise to identify specific adverse events that merit a further, more detailed look using the narrow focused approach. Danger of being swamped by vast quantities of heterogeneous data and of inappropriate pooling. Broad, non-specific evaluations can be resource-intensive and may yield a diverse amount of information from which it is difficult to draw any meaningful conclusions. Detection of previously unrecognized adverse effects may be better addressed through primary surveillance than in a systematic review [3]