Slide 1
A review starts with a defined question
A systematic review uses explicit methods to find and assess research addressing a question. Its aim is a transparent account of the relevant evidence.
More to Read
The question determines which populations, interventions and outcomes qualify. Setting those criteria before seeing the results reduces opportunities to select only studies that support a preferred answer.
Slide 2
Searching must reach beyond familiar papers
Reviewers search specified sources using documented strategies. A convenient handful of well-known studies may miss important evidence.
More to Read
Different databases cover different journals and disciplines. Trial registries and other sources can also help identify studies whose results are less visible in the published literature.
Slide 3
Selection leaves an inspectable trail
Reports explain which studies were included and why others were excluded. Readers can then evaluate how the evidence set was assembled.
More to Read
One study may produce several articles. Reviewers need to recognize related reports so that the same participants are not mistakenly counted as separate independent studies.
Slide 4
Pooling is a separate decision
A meta-analysis combines numerical results statistically. A systematic review does not have to pool studies when their differences make a combined estimate misleading.
More to Read
Differences in participants, interventions and measurement can matter clinically even when a calculation is possible. A single summary number should not erase distinctions needed to understand what the studies actually tested.
Slide 5
A methodical review can still find uncertainty
A systematic process makes evidence easier to assess; it cannot create strong evidence where studies are weak or missing. Conclusions should reflect those limits.
More to Read
The evidence base also changes as new research appears. Search dates and update methods help readers understand the period covered, rather than treating a review as a timeless final verdict.
Sources
- Searching for and selecting studies
Cochrane Handbook, chapter 4
- Analysing data and undertaking meta-analyses
Cochrane Handbook, chapter 10