Filtering a search
Filtering a search
From master's level and upwards, we recommend that you use automatic search filtering with great caution!
- When you use filters from each database, you only find articles that are indexed. Not all articles available in the database are indexed.
- Those who index can make mistakes.
- Be very careful when using the human filter.
- Both Cochrane and Campbell Collaboration recommend not filtering searches by article language.
- Remember that you must always justify your choices of filters you use!
Below you find some examples of how to use search strategies to make the final filters.
Example 1: Limiting to "Humans"
If you want to limit your search to humans, we recommend that you do not use the Humans filter option in the database. Best practice is to first identify animal experiments, then exclude these from the search. Below you find a selection of search strategies:
Medline via Ovid
From Cochrane Handbook, Technical Supplement to Chapter 4 (p. 70):
not (exp animals/ not humans.sh.)
Medline via PubMed
From Cochrane Handbook, Technical Supplement to Chapter 4 (p. 61):
NOT (animals [mh] NOT humans [mh])
Embase via Ovid
From Embase: Excerpta Medica Database Guide - Limits: Humans only (removes all references with animals):
not ((exp animal/ or exp invertebrate/ or nonhuman/ or animal experiment/ or animal tissue/ or animal model/ or exp plant/ or exp fungus/) not (exp human/ or human tissue/))
PsycINFO
From https://doi.org/10.1177/00236772211045485:
NOT (filter described in Supplemental material 5)
CINAHL via EBSCOhost
From Cochrane Handbook, Technical Supplement to Chapter 4 (p. 66):
NOT (((MH "Animals+") OR (MH "Animal Studies") OR (TI "animal model*")) NOT (MH "human"))
Web of Science
From https://doi.org/10.1177/00236772211045485:
NOT (filter described in Supplemental material 6)
Example 2: Limiting to randomized trials in Ovid MEDLINE
This is the Cochrane Highly Sensitive Search Strategy to identify randomized trials in Ovid MEDLINE: sensitivity- and precision-maximizing version (2023 revision); Ovid format. From Cochrane Handbook, Technical Supplement to Chapter 4 (p. 69-70, Box 3.c), Ovid search syntax:
- exp randomized controlled trial/
- controlled clinical trial.pt.
- randomized.ab.
- placebo.ab.
- drug therapy.fs.
- randomly.ab.
- trial.ti.
- 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
- exp animals/ not humans.sh.
- 9 not 10
From Cochrane Handbook, Technical Supplement to Chapter 4 (p. 69-70, Box 3.c), Ovid search syntax:
- exp denotes a Medical Subject Heading (MeSH) term ‘exploded’;
- .pt. denotes a Publication Type term;
- .ab. denotes a word in the abstract;
- .fs. denotes a ‘floating’ subheading, that is a subheading irrespective of the MeSH term to which it is attached;
- .sh. denotes a Medical Subject Heading (MeSH) term not ‘exploded’;
- .ti. denotes a word in the title.
Methodological search filters
Methodological search filters are search strategies to identify a main element or quality/aspect (for example: study type, age group, guideline, etc). These are search strategies that are tested and proven to be reusable. If you find a relevant search strategy, we recommend that you add it to your own search.
Different search filters can be found here:
- Cochrane Highly Sensitive Search Strategies for identifying randomized trials in MEDLINE
- Embase, CINAHL (Cochrane Handbook, Technical Supplement to Chapter 4, p. 57-67)
- CADTH Search Filters Database
- InterTASC Information Specialists' Sub-Group's Search Filter Resource
- Hedges Project from Mc Master University, Health Information Research Unit
- Search Strategy Used to Create the Systematic Reviews Subset on PubMed
