A systematic review has a number of features distinguishing it from merely searching systematically.
It aims to identify as many relevant studies as possible, even if some will be later excluded on technical grounds.
It is also
The inclusion and exclusion criteria may be based on participant recruitment and follow-up, randomisation, sampling or other details of methodology, and validity. In critical appraisal the significance and generalizability of findings are also assessed.
You might not need a systematic review. It's a scholarly research project usually undertaken by experts.
If you need an authoritative source summarising the evidence available, a Cochrane review or clinical guidelines may be more appropriate - or perhaps you could conduct a rapid review.
If you're unsure of the extent of the literature, or still finalising the inclusion and exclusion criteria, a scoping review is indicated.
Step 1 : Develop a Research Question and Review Approach
Does the question need answers, a decision or the best estimate?
If it needs to be fast and authoritative, conduct a rapid review from the best resources.
Scoping reviews – or a systematic review – take more time and aim to cover more or all available resources.
What will be an acceptable answer?
Is <this> intervention with <these> patients more likely to give <these> outputs than another intervention?
Step 2 : Identify Resources and Build a Search Strategy
Use resources selected for coverage and reputation.
Every question has angles and contexts.
Search with a distinct set of words - concepts - targeting each of the main facets of the question.
Adapt the strategy for searching in each resource.
Record when, where and how you searched and the results.
Save, identify and deduplicate the results for critical appraisal.
Step 3 : Analyse and Report the Results
The search strategy will not have filtered out all irrelevant results. Refine the strategy. Apply exclusion criteria.
Screen out inappropriate studies using exclusion criteria, recording what is excluded and why.
A review matrix and summary tables can help with compiling results.
A forest plot can visualise statistical results.