Literature Searching and Reviews

A search protocol is a plan to follow, whereas a search log is a more informal record/documentation of your search.

The search protocol should describe the rationale (purpose of the literature search), hypothesis, how and where to search for literature, and other methods used. The search protocol also makes it possible to minimize bias in the search process.

When preparing a review for publication, you should prepare a general protocol that contains a comprehensive description of the entire review - including purpose and methodology etc. More on protocols see below. If you are a researcher, it can be registered in PROSPERO, which is an international database of pre-registered systematic reviews within health, social care, welfare, public health, education, crime, etc. with a healthcare outcome. 

• Background for the search/review (rational)
• Problem formulation/Problem orientation
• Methods
  • Choice of search strategy
  • In- and exclusion criteria
  • Choice of database or other information source
• Data synthesis
• Validation/ Evaluation/ Conclusion
• Documentation

Search profile (strategy and log) 

In areas where formal search protocols are not required, it can still be a great idea to document your thinking and searches. This makes it easier to get guidance, share it with others or reuse it for a later project. In these cases, you can basically do what you want, but we have prepared a few simple techniques that you can use as a starting point. 

The search strategy should consist of two elements:

1. An overview of keywords, e.g. a block search, with upper and lower terms, in different languages (if applicable) (with possible expansion if there are several relevant core terms).

Block searching form

2. A search strategy with description of choices on databases and other resources. Not in detail, but just in a list. Finally, excellent to have some overall reflections on why you choose the particular databases - or deselect some. This is also to make it easier for yourself to remember later.
Important: there might be big differences in what is relevant for each project.

Search log and search string

Once you have selected your core concepts and search resources, you can perform an actual search customized for the different elements and databases. This means that you need to find out which truncation characters and other special characters are used in your selected resources and then you can write up your search before you start - or just go for it.
For each database/resource, it's a good idea to document your search. You'll be repeating it several times, so good to be able to go back and see what results you got last time - even if you change something about the search along the way. If you need to search many times or in many places, you may want to create a table for each database.

According to the Cochrane Collaboration, a protocol is a plan to be followed in a study. As part of the preparation of a systematic review article, and to minimize bias in the process, it is therefore most appropriate to prepare a general protocol that describes the rationale, hypothesis, how and where to search for literature, and what other methods are used in the preparation of the systematic review article (1).
It is therefore essential to prepare a protocol - also for review types other than systematic reviews.

Guides are available to help you create protocols:

• PRISMA for systematic review protocols (PRISMA-P) lists a number of different points that should be included when creating a protocol.
• Joanna Briggs Institute (JBI) refers to the JBI Manual for Evidence Synthesis: Scoping Review Chapter, which also includes guidance for creating protocols for scoping reviews.

Protocols may be registred in PROSPERO, which is an international database of pre-registered systematic reviews within health, social care, welfare, public health, education, crime, etc. where there is a health outcome. Protocols for systematic reviews can thus be registered in PROSPERO if the systematic review and thus the protocol falls under the current requirements of PROSPERO. Protocols for scoping reviews cannot be registered in PROSPERO.
If the subject of the review does not fall under the conditions set by PROSPERO, a protocol can be made based on eg PRISMA-P. The protocol can then be uploaded to a freely accessible location eg Open Science Framework (OSF) Registries, Figshare, medRxiv or other websites.

You can also publish the protocol in a scientific journal, such as BMJ Open or Systematic Reviews or other journals.

References:
(1). Cumpston M, Flemyng E. Chapter II: Planning a Cochrane Review. Cochrane Protocols In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.5. Cochrane, 2024