Consider whether it is important to modify or add new objectives to make the review relevant to its users.

Consider whether the review will be split, merged with another review or otherwise changed substantially. If so, a new protocol might be warranted and the MECIR conduct standards should be followed rather than these update standards. It will be necessary to agree the approach to updating the review with the CRG.

MECIR conduct standards C1, C2

Consider whether it is necessary to modify or add outcomes to ensure all user-important outcomes, including adverse effects, are addressed. Define which outcomes are primary outcomes and which are secondary outcomes. Keep the total number of outcomes as small as possible. Consider core outcome sets where available. Prioritize outcomes that will be assessed with the GRADE considerations.

MECIR conduct standards C3, C14-C18, C23

There are four considerations in planning search methods for updates:

1. Changes to eligibility criteria may require the search methods to be modified, or additional search strategies to be developed.
2. Additional sources might need to be searched (e.g. trials registers) if not searched for the last published version of the review. Consideration should also be given to the importance of searching data repositories and information available from regulatory agencies.
3. The update search (for unchanged eligibility criteria) will normally be limited to material added or indexed after the date of the previous search. The yield of the previous searches may be useful to decide whether the full search is repeated or whether only a subset of sources should be searched for the update.
4. The original database search strategies may need to be modified, for example by adding search terms, adding new database subject headings, or by removing unhelpful search terms that identified many irrelevant studies in the original search.

MECIR update standards U6 and UR3

See Handbook Section IV.3.4

Study flow diagrams in Cochrane systematic review updates: an adapted PRISMA flow diagram

Decide if changes are required to make better use of existing data or to incorporate new data by referring to the current version of the Handbook. Recent developments in ’Risk of bias’ assessment, statistical methods or narrative synthesis approaches may lead to more inclusive or more robust synthesis of the evidence.

The GRADE assessment will require evaluation of risk of bias, inconsistency, imprecision, indirectness and publication bias. See MECIR update standard U11.

If a ‘Summary of findings’ table is not included in the current version, decide on the main outcomes and comparisons to be included and ensure that the relevant data have been (or will be) collected. See MECIR update standard UR5

MECIR update standards U9-U10