A population search filter for hard-to-reach populations increased search efficiency for a systematic review.
OBJECTIVE
This article discusses how hard-to-reach population groups were conceptualized into a search filter. The objectives of this article were to (1) discuss how the authors designed a multistranded population search filter and (2) retrospectively test the effectiveness of the search filter in capturing all relevant populations (eg, homeless people, immigrants, substance misusers) in a public health systematic review.


METHODS
Systematic and retrospective analysis via a case study. Retrospective analysis of the search filter was conducted by comparing the MEDLINE search results retrieved without using the search filter against those retrieved with the search filter. A total of 5,465 additional results from the unfiltered search were screened to the same criteria as the filtered search.


RESULTS
No additional populations were identified in the unfiltered sample. The search filter reduced the volume of MEDLINE hits to screen by 64%, with no impact on inclusion of populations.


CONCLUSIONS
The results demonstrate the effectiveness of the filter in capturing all relevant UK populations for the review. This suggests that well-planned search filters can be written for reviews that analyze imprecisely defined population groups. This filter could be used in topic areas of associated comorbidities, for rapid clinical searches, or for investigating hard-to-reach populations.
PenTAG, University of Exeter Medical School, University of Exeter, Veysey Building, Salmon Pool Lane, Exeter, EX2 4SG, UK. Electronic address: Christopher.Cooper@exeter.ac.uk.
Chris
C
Cooper
National Institute for Health and Care Excellence, City Tower, Piccadilly Plaza, Manchester, M1 4BT, UK.
Paul
P
Levay
Department of Social & Environmental Health Research, London School of Hygiene & Tropical Medicine, 15-17 Tavistock Place, London WC1H 9SH, UK.
Theo
T
Lorenc
School of Health Sciences, City University London, Northampton Square, London EC1V 0HB, UK.
Gillian M
GM
Craig
D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods; D016239:MEDLINE; D011634:Public Health; D012189:Retrospective Studies; D000078202:Systematic Reviews as Topic
Disadvantaged; Equity; Hard to reach; Information retrieval; Information science; Literature searching; Search filter; Systematic review methodology; Tuberculosis; Vulnerable