The search process needs to be documented in enough detail throughout the process to ensure that it can be reported correctly in the review, to the extent that all the searches of all the databases are reproducible. It should be borne in mind at the outset that the full search strategies for each database will need to be included in an Appendix of the review. The search strategies will need to be copied and pasted exactly as run and included in full, together with the search set numbers and the number of records retrieved. The search strategies should not be re-typed as this can introduce errors. A recent study has shown lack of compliance with guidance in the Handbook with respect to search strategy description in Cochrane reviews (Sampson 2006). In the majority of CRGs, the Trials Search Co-ordinators are now asked to comment on the search strategy sections of a review as part of the sign-off process prior to a review being considered ready for publication in the CDSR. It is, therefore, recommended that review authors should seek guidance from their Trials Search Co-ordinator at the earliest opportunity with respect to documenting the process to facilitate writing up this section of the review. As mentioned elsewhere in this chapter, it is particularly important to save locally or file print copies of any information found on the internet, such as information about ongoing trials, as this information may no longer be accessible at the time the review is written up.
In the light of the new guidance introduced in March 2011 that review authors are strongly encouraged to include a study flow diagram as recommended by the PRISMA statement (see Chapter 4, Section 4.5) and the further details as to what the flow diagram should present (see Chapter 11, Section 11.2.1), that is:
number of unique records identified by the searches;
number of records excluded after preliminary screening (e.g. of titles and abstracts); and
number of records retrieved in full text;
it is recommended that appropriate notes are taken during the search process to ensure that the flowchart, if used, can be completed correctly.