Search filters are search strategies that have been devised and tested to filter the results of your search from large, general purpose databases including MEDLINE, EMBASE, and PsycINFO. It is also known as "hedges" used to limit search results by
You may find the built-in search filters provided by the specific databases. For systematic review, we would recommend you to use a validated search filter if there is a need to apply it. If you reuse search filters that others have developed, you should acknowledge the sources that you cite. Please refer to the "Search filters resources" in the next section to explore further.
Cochrane Handbook See Part 2 - Section 6.4.11: Search Filters
Pubmed Clinical Queries Enter your search term and your results will be automatically categorised into Clinical Study categories, Systematic Reviews and Medical Genetics.
CareSearch Search filters for palliative care, heart failure, dementia, residential aged care and dementia.
BMJ Clinical Evidence Study design search filters
CINAHL Clinical Queries allow the user to limit searches using specific search strategies to aid in retrieving scientifically sound and clinically relevant study reports indexed in CINAHL databases.
The Covid-19 search filter was developed by NUS Medical Library (not validated) . Please feel free to adapt the search strategy to meet your research needs.
Cochrane Highly Sensitive Search Strategy for identifying randomized trials in MEDLINE(OVID)
((randomized controlled trial.pt. or controlled clinical trial.pt. or randomized.ab. or placebo.ab. or drug therapy.fs. or randomly.ab. or trial.ab. or groups.ab.) not (exp animals/ not humans.sh.))
Refer to the Cochrane Handbook for details.
Cochrane RCT Filter for EMbase
Glanville J, Foxlee R, Wisniewski S, Noel-Storr A, Edwards M, Dooley G. Translating the Cochrane EMBASE RCT filter from the Ovid interface to Embase.com: a case study. Health Info Libr J. 2019 Jul 22. doi: 10.1111/hir.12269 .
For Embase RCT filter for Embase.com and Embase RCT filter for Ovid (30 April 2023 revision), please refer to the InterTASC ISSG Search filter for Embase RCT.
CINAHL (EBSCOhost) filter/hedge for controlled clinical trials:
(MH randomized controlled trials OR MH double-blind studies OR MH single-blind studies OR MH random assignment OR MH pretest-posttest design OR MH cluster sample OR TI (randomised OR randomized) OR AB (random*) OR TI (trial) OR (MH (sample size) AND AB (assigned OR allocated OR control)) OR MH (placebos) OR PT (randomized controlled trial) OR AB (control W5 group) OR MH (crossover design) OR MH (comparative studies) OR AB (cluster W3 RCT)) NOT ((MH animals+ OR MH animal studies OR TI animal model*) NOT MH human)
Source: Glanville J, Dooley G, Wisniewski S, Foxlee R, Noel‐Storr A. Development of a search filter to identify reports of controlled clinical trials within CINAHL Plus. Health Information & Libraries Journal. 2019 Mar;36(1):73-90.
Searching Scopus for "Randomised Control Trials" .
( INDEXTERMS ( "clinical trials" OR "clinical trials as a topic" OR "randomized controlled trial" OR "Randomized Controlled Trials as Topic" OR "controlled clinical trial" OR "Controlled Clinical Trials" OR "random allocation" OR "Double-Blind Method" OR "Single-Blind Method" OR "Cross-Over Studies" OR "Placebos" OR "multicenter study" OR "double blind procedure" OR "single blind procedure" OR "crossover procedure" OR "clinical trial" OR "controlled study" OR "randomization" OR "placebo" ) ) OR ( TITLE-ABS-KEY ( ( "clinical trials" OR "clinical trials as a topic" OR "randomized controlled trial" OR "Randomized Controlled Trials as Topic" OR "controlled clinical trial" OR "Controlled Clinical Trials as Topic" OR "random allocation" OR "randomly allocated" OR "allocated randomly" OR "Double-Blind Method" OR "Single-Blind Method" OR "Cross-Over Studies" OR "Placebos" OR "cross-over trial" OR "single blind" OR "double blind" OR "factorial design" OR "factorial trial" ) ) ) OR ( TITLE-ABS ( clinical trial* OR trial* OR rct* OR random* OR blind* ) )
This filter was developed by NUS Medical Library (not validated) using MESH and EMTREE terms as Index terms and Keywords.
Useful to search in Scopus for RCTs.
These are the qualitative research filters that you can try to identify qualitative studies as appropriate.
1) Health Services Research (HSR) PubMed Queries
2) Please click this link to explore the use of other qualitative filters.
Unniversity of Alberta's Health Sciences search filters on Lower and Lower Middle Income Countries at https://guides.library.ualberta.ca/c.php?g=342568&p=5035704
EPOC LMIC filters at https://epoc.cochrane.org/lmic-filter
World bank country classification at https://datahelpdesk.worldbank.org/knowledgebase/topics/19280-country-classification