Figure 1 depicts the study selection process. Following a literature search (which is periodically updated), titles and abstracts are reviewed. If a citation is selected for retrieval, the full article is retrieved and the study selection criteria applied. If the article is identified for exclusion, it is reviewed by a second reviewer. If the first and second reviewers disagree as to whether to include the article, the disagreement is resolved by consensus or by the decision of a third reviewer.  If an article is chosen for inclusion, the data in the article are abstracted and fact-checked by a second reviewer. Again, in case of discrepancy, this is resolved by consensus or by a third reviewer. Summary evidence tables are then created from the data abstraction tables. Also, the reference lists of all included articles are reviewed to identify additional studies for potential inclusion.

Figure 1Study selection process

From: Methods

Cover of Comparative Effectiveness and Safety of Radiotherapy Treatments for Head and Neck Cancer
Comparative Effectiveness and Safety of Radiotherapy Treatments for Head and Neck Cancer [Internet].
Comparative Effectiveness Reviews, No. 20.
Samson DJ, Ratko TA, Rothenberg BM, et al.

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