Table 1 Forming an overview question and defining the type and objective of an overview
Focus of question | Question about the effect of intervention(s) | Question about diagnostic test accuracy | Question about prognosis/prevelence | Questions about disease aetiology or risk factors | Question about qualitative views or experiences | |
|---|---|---|---|---|---|---|
Population | Is the focus on one discrete population, or bringing together evedence from different populations? | |||||
Intervention/phenomenon of interest | Is the focus on one specific intervention or a range of different possible interventions? | Is the focus on one single medical test or a range of different medical tests? | Is the focus on overall prognosis, prognostic factors or risk prediction (prognostic models)? | Is the focus on associations between disease indices and risk factors, or the impact of risk factors on single/multiple outcomes? | Is the focus on qualitative aspects of an intervention, such as views or experiences of a particular group of people? | |
Outcome | Is the focus on one specific outcome (including adverse events) or a range of different outcomes? | |||||
Context/setting | Describe the context of setting of interest | |||||
Type of review | Review of RCTs | Review of intervention studies | Reviews of diagnostic test accuracy studies | Review of prognosis/prevalence | Reviews of associated risk factors | Review of qualitative studies |
Type of overview | Overview of intervention reviews | Overview of diagnostic test accuracy reviews | Overview of reviews of prognostic studies | Overview of reviews of risk factors | Overview of qualitative reviews | |
Overview objective | To summarise evidence from more than one systematic review of different interventions for the same condition or problem; OR | To summarise evidence from more than one systematic review of diagnostic test accuracy assessing the same medical test to address the same condition of problem; OR | To summarise evidence about prognosis/prevalence from more than one systematic reviews. | To summarise systematic review evidence about risk factors not directly aligned to predictive values. | To summarise systematic review evidence relating to qualitative views or experiences. | |
| Â | To summarise evidence from more than one systematic review of the same intervention for the same condition of problem where different outcomes are addressed in different systematic reviews; OR | To summarise evidence from more than one systematic review of diagnostic test accuracy assessing different medical tests to address the same condition or problem. | Â | Â | Â | |
| Â | To summarise evidence from more than one systematic review of the same intervention for different conditions, problems or populations; OR | Â | Â | Â | Â | |
| Â | To summarise evidence about adverse effects of an intervention from more than one systematic review of use of the intervention for one or more conditions. | Â | Â | Â | Â | |