How do I rerun a systematic-review search during revision without mixing old and new records?

Freeze the original search log as a dated record, rerun the same documented strategies with a new date boundary, deduplicate the exported update against the original set, and report the added records separately so both search histories stay intact. The Cochrane Handbook treats documenting searches and managing records as distinct parts of the search process, so the original log and the update should remain separate artifacts with their own dates.

Step-by-step rerun

1. Freeze the original search log. Save the original strategies, sources, and search dates exactly as they were run, and stop editing that file. This becomes the baseline the revision is measured against.
2. Rerun each documented strategy with a new date boundary. Reuse the same databases, sources, and strategy strings from the frozen log, changing only the date limit to cover the period since the original search. Record the new run date alongside each strategy.
3. Export the update as its own file. Keep the new export separate from the original result set so the two can be compared and reported independently.
4. Deduplicate the update against the original set. Use duplicate detection to identify records already captured in the original search, and merge or remove those matches so the update reflects only newly retrieved items. Zotero's duplicate detection identifies potential duplicates and provides a merge interface that preserves collections and tags while combining item records.
5. Report added records separately. Present the new records as an addition to the original set, with the original and updated search histories both visible.

What to preserve in the revision

Keep both search histories: the original strategies with their original dates, and the rerun strategies with the new date boundary and run date. PRISMA 2020 provides a checklist and flow diagrams for transparent reporting of why a review was done, what methods were used, and what studies were found and included, so the added records and the updated search dates belong in that reporting structure.

Decision point

After deduplication, check whether the update contains records not present in the original set. Those records are the added set to screen and report; matches removed during deduplication stay attributed to the original search. If a record's status is unclear after deduplication, keep it in the update file and resolve it during screening instead of deleting it.