Search Filters

A search filter is a search string which can capture specific study types. Videncentret has compiled an overview of search filters which can be used to identify various kinds of studies. If you need a search filter, you can contact Videncentret.

Be aware of the fact that the use of methodological filters may result in exclusion of relevant studies, and you should therefore consider leaving out methodological filters (Leeflang, Cholten, Rutjes, Reitsma, and Bossuyt, 2006). Therefore, it will be a good idea to evaluate the filters before using them (Glanville et al., 2008).

Glanville, J., Bayliss, S., Booth, A., Dundar, Y., Fernandes, H., Fleeman, N. D., . . . Welch, K. (2008). So many filters, so little time: the development of a search filter appraisal checklist. J Med Libr Assoc, 96(4), 356-361. doi: 10.3163/1536-5050.96.4.011.

Leeflang, M. M., Scholten, R. J., Rutjes, A. W., Reitsma, J. B., & Bossuyt, P. M. (2006). Use of methodological search filters to identify diagnostic accuracy studies can lead to the omission of relevant studies. J Clin Epidemiol, 59(3), 234-240. doi: 10.1016/j.jclinepi.2005.07.014.

Diagnostic studies are not simple to identify using a filter and Beynon et al (2013) does not find a single filter with a recall value of over 90 (meaning the filter will find at least 90% of the relevant studies) and precision above 10 (meaning that at least 10% of the search results will be relevant studies).

Below is a compilation of two tested filters with very high recall (see Leeflang, 2006 for documentation). The filter is tailored for PubMed. Click the text field to select the combined filter (which can then be copied).


Here is additionally a list of search terms and their corresponding sensitivity and precision. This list is very broad and yields a lot of irrelevant results:

TermSensitivityPrecision
predict*48.236.4
diagnos*80.716.8
sensitiv*36.133.0
accura*24.146.5
screen*19.339.0
specific*35.019.9
test*49.413.7
detect*32.518.1
positiv*28.920.2
negativ*20.520.0
evaluat*27.711.6
analy*38.67.7
risk*22.912.8
assess*24.111.6
scor*13.317.2
assay*13.316.7
differen*28.97.5
measure*25.37.6
examin*20.58.4
determ*22.97.4

For Medline (Ovid)

  1. 1. exp Diagnosis/
  2. exp “Sensitivity and Specificity”/
  3. exp Reference Values/
  4. exp False Positive Reactions/
  5. exp False Negative Reactions/
  6. exp Mass Screening/
  7. diagnos*.mp.
  8. sensitivity.mp.
  9. specificity.mp.
  10. predictive value*.mp.
  11. reference value*.mp.
  12. ROC*.mp.
  13. likelihood ratio*.mp.
  14. monitoring.mp.
  15. screening.mp.
  16. false positive.mp.
  17. false negative.mp.
  18. accuracy.mp.
  19. (predictive and value*).mp. [mp=title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]
  20. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19


For Embase (Ovid)

  1. 1. exp diagnosis/
  2. exp “sensitivity and specificity”/
  3. exp reference value/
  4. exp false positive result/
  5. exp false negative result/
  6. exp mass screening/
  7. diagnos*.mp.
  8. sensitivity.mp.
  9. specificity.mp.
  10. predictive value*.mp.
  11. reference value*.mp.
  12. ROC*.mp.
  13. likelihood ratio*.mp.
  14. monitoring.mp.
  15. screening.mp.
  16. false positive.mp.
  17. false negative.mp.
  18. accuracy.mp.
  19. (predictive and value*).mp. [mp=title, abstract, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword]
  20. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19


Literature

Beynon R, Leeflang MM, McDonald S, Eisinga A, Mitch ell RL, Whiting P, Gl anville JM. Search strategies to identify diagnostic accuracy studies in MEDLINE and EMBASE. Cochrane Database of Systematic Reviews 2013, Issue 9. Art. No.: MR000022. DOI: 10.1002/14651858.MR000022.pub3
Lucas M. Bachmann, MD, Reto Coray, MD, Pius Estermann, MD, and Gerben ter Riet, MD, PhD. Identifying Diagnostic Studies in MEDLINE: Reducing the Number Needed to Read. J Am Med Inform Assoc. 2002 Nov-Dec; 9(6): 653-658.

Click the text field below to select the filter text.


de Vries RB1, Hooijmans CR, Tillema A, Leenaars M, Ritskes-Hoitinga M.
Updated version of the Embase search filter for animal studies.
Lab Anim. 2014 Jan;48(1):88. doi: 10.1177/0023677213494374. Epub 2013 Jul 8.

de Vries RB, Hooijmans CR, Tillema A, Leenaars M, Ritskes-Hoitinga M.
A search filter for increasing the retrieval of animal studies in Embase.
Lab Anim. 2011 Oct;45(4):268-70. doi: 10.1258/la.2011.011056. Epub 2011 Sep 2.

PubMed Filter

Click the text field below to select the filter text.


Hooijmans CR1, Tillema A, Leenaars M, Ritskes-Hoitinga M.
Enhancing search efficiency by means of a search filter for finding all studies on animal experimentation in PubMed.
Lab Anim. 2010 Jul;44(3):170-5. doi: 10.1258/la.2010.009117. Epub 2010 Jun 15.

Cochrane Handbook contains filters to limit searches to human studies in PubMed and Medline (Ovid).

PubMed


Medline (Ovid)


Embase (Ovid)


Literature

Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from http://training.cochrane.org/handbook/, Chapter 2, section 6.4.11.

In some cases, it will be most relevant simply to filter by using qualitativefindings and interviews instead of using a broader free-text filter (Grant, 2000; Flemming & Briggs, 2007). But you may also see examples where the 2 types of filtering will complement but not substitute one another (Shaw et al., 2004).

Three types of filters for searching for qualitative studies (Jenskins, 2004):

  1. subjective filters based on experience
  2. subjective filters which have been tested
  3. objectively developed filters based on word frequency

We will begin with the last mentioned type. Many databases offer a filter that limits searches to qualitative studies. These filters have been developed on the basis of word frequency in a number of qualitative articles. Evidence for the filters can be found here:

CINAHL: Wilcynski, Marks og Haynes (2007), EMBASE: Walters, Wilczynski, Haynes, & Hedges, Team (2006), MEDLINE: Wong, Wilczynski, Haynes & Hedges, Team. (2004) og PsycInfo: McKibbon, Wilczynski & Haynes (2006).

Filters focusing on recalling as much as possible of the qualitative research (high recall):

Embase filter: interview*.tw. OR qualitative.tw. OR exp health care organization

PsycInfo filter: experience*.mp. OR interview*.tw. OR qualitative*.tw.

PubMed filter: interview*[Title/Abstract] OR psychology[Subheading:noexp] OR health services administration[MeSH Term]

Cinahl filter: ((MH “study design+” not MM “study design+”) or MH “attitude” or (MH “interviews+” not MM “interviews+”))

We will now return to the two first types of filters: viz. the subjective ones. You can also use a more complex filter, typically based upon the experience of librarians and in some cases later tests. Here are examples of these filters which you can copy and paste directly into the search field of a database.

Cinahl

Click the text field below to select the filter text.


The filter is based on experience and is untested: Cinahl-search

PubMed

Click the text field below to select the filter text.


The filter is based on experience and is untested: PubMed-search

PsycInfo

Click the text field below to select the filter text.


The filter is based on experience and is untested: Saini, Michael, & Shlonsky, Aron. (2012). Systematic synthesis of qualitative research. New York: Oxford University Press.

The following version works with APA:


There are not many different tests of filters. Some examples are Grant, 2000; Flemming & Briggs, 2007, and Shaw et al., 2004.

Litteratur

Flemming, K., & Briggs, M. (2007). Electronic searching to locate qualitative research: evaluation of three strategies. Journal of Advanced Nursing, 57(1), 95-100. doi: DOI 10.1111/j.1365-2648.2006.04083.x
Grant, M. J. (2000). Searching for qualitative studies on the Medline database: The development of an optimal search strategy. Department of Information and Library Studies Aberystwyth, University of Wales.
Jenkins, M. (2004). Evaluation of methodological search filters-a review. Health Information & Libraries Journal, 21(3), 148-163.
McKibbon, K. A., Wilczynski, N. L., & Haynes, R. B. (2006). Developing optimal search strategies for retrieving qualitative studies in PsycINFO. Evaluation and the Health Professions, 29(4), 440-454.
Saini, Michael, & Shlonsky, Aron. (2012). Systematic synthesis of qualitative research. New York: Oxford University Press.
Shaw, R. L., Booth, A., Sutton, A. J., Miller, T., Smith, J. A., Young, B., . . . Dixon-Woods, M. (2004). Finding qualitative research: an evaluation of search strategies. BMC Med Res Methodol, 4, 5. doi: 10.1186/1471-2288-4-5
Walters, L. A., Wilczynski, N. L., Haynes, R. B., & Hedges, Team. (2006). Developing optimal search strategies for retrieving clinically relevant qualitative studies in EMBASE. Qualitative Health Research, 16(1), 162-168. doi: 10.1177/1049732305284027
Wilczynski, N. L., Marks, S., & Haynes, R. B. (2007). Search strategies for identifying qualitative studies in CINAHL. Qualitative Health Research, 17(5), 705-710. doi: 10.1177/1049732306294515
Wong, S. S., Wilczynski, N. L., Haynes, R. B., & Hedges, Team. (2004). Developing optimal search strategies for detecting clinically relevant qualitative studies in MEDLINE. Stud Health Technol Inform, 107(Pt 1), 311-316.

Observationelle / cohort studies

List of search terms from: Fraser, C., Murray, A., & Burr, J. (2006). Identifying observational studies of surgical interventions in MEDLINE and EMBASE. BMC Medical Research Methodology, 6, 41. doi:10.1186/1471-2288-6-41

Candidate search terms for EMBASE:

  1. Case report/
  2. Clinical trial/
  3. Cohort analysis/
  4. Comparative study/
  5. Controlled study/
  6. Follow-up study/
  7. Major clinical study/
  8. Prospective study/
  9. Retrospective study/
  10. Treatment outcome/
  11. baseline
  12. case control$
  13. case series
  14. cases
  15. chang$
  16. cohort
  17. compar$ or compara$
  18. consecutive$
  19. evaluat$
  20. follow$
  21. non compara$ or noncompara$
  22. non random$ or nonrandom$
  23. observational
  24. postoperat$ or post operat$
  25. preoperat$ or pre operat$
  26. prospective$
  27. retrospective$
  28. reviewed
  29. cohort$
  30. compare$ or compara$
  31. follow$
  32. prospective$
  33. retrospective$
  34. postoperat$ or post operat$
  35. preoperat$ or pre operat$

Candidate search terms for MEDLINE:

  1. Case-control studies/
  2. Cohort studies/
  3. Comparative studies/
  4. Follow-up studies/
  5. Prospective studies/
  6. Retrospective studies/
  7. Time factors/
  8. Treatment outcome/
  9. Case reports.pt
  10. Clinical trial.pt
  11. Evaluation studies.pt
  12. baseline
  13. case control$
  14. case series
  15. cases
  16. chang$
  17. cohort
  18. compare$ or compara$
  19. consecutive$
  20. evaluat$
  21. follow$
  22. non compara$ or noncompara$
  23. non random$ or nonrandom$
  24. observational
  25. post operat$ or postoperat$
  26. pre operat$ or preoperat$
  27. prospective$
  28. retrospective$
  29. reviewed
  30. case control
  31. cohort
  32. compare$ or compara$
  33. follow$
  34. prospective$
  35. retrospective$
  36. postoperat$ or post operat$
  37. preoperat$ or pre operat$
Filters developed by SIGN

The Observational Studies search filter used by SIGN has been developed in-house to retrieve studies most likely to meet SIGN's methodological critieria.

EMBASE:

  1. Clinical study/
  2. Case control study
  3. Family study/
  4. Longitudinal study/
  5. Retrospective study/
  6. Prospective study/
  7. Randomized controlled trials/
  8. 6 not 7
  9. Cohort analysis/
  10. (Cohort adj (study or studies)).mp.
  11. (Case control adj (study or studies)).tw.
  12. (follow up adj (study or studies)).tw.
  13. (observational adj (study or studies)).tw.
  14. (epidemiologic$ adj (study or studies)).tw.
  15. (cross sectional adj (study or studies)).tw.
  16. Or/1-5,8-15

MEDLINE:

  1. Clinical study/
  2. Case control study
  3. Family study/
  4. Longitudinal study/
  5. Retrospective study/
  6. Prospective study/
  7. Randomized controlled trials/
  8. 6 not 7
  9. Cohort analysis/
  10. (Cohort adj (study or studies)).mp.
  11. (Case control adj (study or studies)).tw.
  12. (follow up adj (study or studies)).tw.
  13. (observational adj (study or studies)).tw.
  14. (epidemiologic$ adj (study or studies)).tw.
  15. (cross sectional adj (study or studies)).tw.
  16. Or/1-5,8-15

CINAHL:

  1. Prospective studies/
  2. Exp case control studies/
  3. Correlational studies/
  4. Nonconcurrent prospective studies/
  5. Cross sectional studies/
  6. (cohort adj (study or studies)).tw.
  7. (observational adj (study or studies)).tw.
  8. or/1-7
Cohort study strategy

EMBASE:

  1. exp cohort analysis/
  2. exp longitudinal study/
  3. exp prospective study/
  4. exp follow up/
  5. cohort$.tw.
  6. or/1-5

MEDLINE:

  1. exp cohort studies/
  2. cohort$.tw.
  3. controlled clinical trial.pt.
  4. epidemiologic methods/
  5. limit 4 to yr=1971-1988
  6. or/1-3,5
Cohort and case-control strategy

EMBASE:

  1. exp cohort analysis/
  2. exp longitudinal study/
  3. exp prospective study/
  4. exp follow up/
  5. cohort$.tw.
  6. exp case control study/
  7. (case$ and control$).tw.
  8. or/1-7

MEDLINE:

  1. exp cohort studies/
  2. cohort$.tw.
  3. controlled clinical trial.pt.
  4. epidemiologic methods/
  5. limit 4 to yr=1966-1989
  6. exp case-control studies/
  7. (case$ and control$).tw.
  8. or/1-3,5-7
Cohort, case-control, and case series strategy

EMBASE:

  1. exp cohort analysis/
  2. exp longitudinal study/
  3. exp prospective study/
  4. exp follow up/
  5. cohort$.tw.
  6. exp case control study/
  7. (case$ and control$).tw.
  8. exp case study/
  9. (case$ and series).tw.
  10. or/1-9

MEDLINE:

  1. exp cohort studies/
  2. cohort$.tw.
  3. controlled clinical trial.pt.
  4. epidemiologic methods/
  5. limit 4 to yr=1966-1989
  6. exp case-control studies/
  7. (case$ and control$).tw.
  8. (case$ and series).tw.
  9. or/1-3,5-8
Cohort, case-control, case series, and case study strategy

EMBASE:

  1. exp cohort analysis/
  2. exp longitudinal study/
  3. exp prospective study/
  4. exp follow up/
  5. cohort$.tw.
  6. exp case control study/
  7. (case$ and control$).tw.
  8. exp case study/
  9. (case$ and series).tw.
  10. case report/
  11. (case$ adj2 report$).tw.
  12. (case$ adj2 stud$).tw.
  13. or/1-12

MEDLINE:

  1. exp cohort studies/
  2. cohort$.tw.
  3. controlled clinical trial.pt.
  4. epidemiologic methods/
  5. limit 4 to yr=1966-1989
  6. exp case-control studies/
  7. (case$ and control$).tw.
  8. (case$ and series).tw.
  9. case reports.pt.
  10. (case$ adj2 report$).tw.
  11. (case$ adj2 stud$).tw.
  12. or/1-3,5-11

Filters with high recall (and sensitivity above 80). Here are the 11 best filters combined into one filter for Medline and afterwards adjusted for Embase and PubMed.

PubMed

Click the text field below to select the filter text.


MEDLINE (Ovid)

  1. ((singl* or doubl* or treb* or tripl*) adj (blind$3 or mask$3)).tw.
  2. (allocated adj2 random).tw.
  3. (clin* adj25 trial*).ti, ab.
  4. (clinic* adj trial$1).tw.
  5. (double-blind* or random*).af.
  6. clinical trial.pt.
  7. clinical trials as topic.sh.
  8. controlled clinical trial.pt.
  9. double blind method.sh.
  10. single blind method.sh.
  11. double-blind method.sh.
  12. single-blind method.sh.
  13. drug therapy.fs.
  14. exp clinical trials as topic
  15. exp research design
  16. placebo*.tw.
  17. placebos.sh.
  18. practice guideline.pt.
  19. random allocation.sh.
  20. random*.tw.
  21. Random.af
  22. randomized controlled trial.pt
  23. randomized controlled trials as topic.sh
  24. randomized.ab.
  25. randomly allocated.tw.
  26. randomly.ab.
  27. single-blind method.sh.
  28. trial.ab.
  29. trial.ti.
  30. 1 OR 2 OR 3 OR 4 OR 5 OR 6 OR 7 OR 8 OR 9 OR 10 OR 11 OR 12 OR 13 OR 14 OR 15 OR 16 OR 17 OR 18 OR 19 OR 20 OR 21 OR 22 OR 23 OR 24 OR 25 OR 26 OR 27 OR 28 OR 29
  31. case report. tw.
  32. letter.pt.
  33. historical article.pt.
  34. review of reported cases.pt
  35. review, multicase.pt.
  36. 31 OR 32 OR 33 OR 34 OR 35
  37. 30 NOT 36

Click the text field below to select the filter text.


EMBASE (Ovid)

  1. ((singl* or doubl* or treb* or tripl*) adj (blind*3 or mask$3)).tw.
  2. (allocated adj2 random).tw.
  3. (clin* adj25 trial*).ti,ab.
  4. (clinic: adj trial$1).tw.
  5. (double-blind* or random*).af.
  6. exp “clinical trial (topic)”/
  7. exp double blind procedure/
  8. exp single blind procedure/
  9. exp triple blind procedure/
  10. placebo*.tw.
  11. exp placebo/
  12. exp randomization/
  13. Random.af.
  14. Random*.tw.
  15. exp “randomized controlled trial (topic)”/
  16. randomized.ab.
  17. randomly allocated.tw.
  18. randomly.ab.
  19. trial.ab.
  20. trial.ti.
  21. exp “controlled clinical trial (topic)”/
  22. randomized controlled trial/
  23. “randomized controlled trial (topic)”/
  24. exp controlled clinical trial/

Click the text field below to select the filter text.


Excerpts from McKibbon, K. A., Wilczynski, N. L., & Haynes, R. B. (2009).
Retrieving randomized controlled trials from medline: a comparison of 38 published search filters.

Filters developed around the following paper: Lee, E., Dobbins, M., Decorby, K., McRae, L., Tirilis, D., & Husson, H. (2012). An optimal search filter for retrieving systematic reviews and meta-analyses. BMC Med Res Methodol, 12, 51.

The filters with highest recall (except filters with a specificity of less than 80) are used. If standard deviation is accounted for, there will be filters which cannot unequivocally be considered better than others and in these cases, two-three filters are combined as one large filter to achieve the largest possible recall.

MEDLINE via Ovid: The four best filters (recall was 99-99.5 and specificity was 87-89) have been combined into the following filter:

  1. meta-analysis/
  2. review literature/
  3. review.ab.
  4. review.pt.
  5. review.ti.
  6. meta-analysis.mp,pt.
  7. meta-analy$.tw.
  8. metaanal$.tw.
  9. (systematic$ adj4 (review$ or overview$))
  10. review literature.pt.
  11. search:.tw.
  12. or/1-11
  13. case report/
  14. letter.pt.
  15. historical article.pt.
  16. review of reported cases.pt.
  17. review,multicase.pt.
  18. letter.pt.
  19. comment.pt.
  20. editorial.pt.
  21. or/13-20
  22. 12 not 21

Click the text field below to select the filter text.


PubMed:

Click the text field below to select the filter text.


EMBASE (via Ovid): The two best filters (recall 88-96 and specificity 86-98) have been combined in the following filter:

  1. search:.tw.
  2. review.pt.
  3. meta-analy:.mp.
  4. MEDLINE.tw.
  5. exp systematic review/ or systematic review.tw
  6. meta-analysis/
  7. intervention$.ti
  8. or/1-7

Click the text field below to select the filter text.


CINAHL (via Ovid): the two best filters (recall 96-98 and specificity 94-95) have been combined in the following filter:

  1. meta-analysis.mp.
  2. review.pt.
  3. meta analysis/
  4. systematic review/
  5. systematic review.pt.
  6. (metaanaly$ or meta-analy$).tw.
  7. metanal$
  8. nursing interventions.pt.
  9. (review$ or overview$).ti.
  10. literature review/
  11. exp literature searching/
  12. cochrane$.tw.
  13. synthes$.tw. adj3 (literature$ or research$ or studies or data).tw.
  14. (MEDLINE or medlars or embase or scisearch or psycinfo or psychinfo or psyclit or psychlit).tw,sh.
  15. pooled analy$.tw.
  16. ((data adj2 pool$) and studies).tw.
  17. ((hand or manual$ or database$ or computer$) adj2 search$).tw.
  18. reference databases/
  19. ((electronic$ or bibliographic$) adj2 (database$ or data base$)).tw.
  20. (review or systematic-review or practice-guidelines).pt.
  21. (review$ or overview$).ab.
  22. (systematic$ or methodologic$ or quantitativ$ or research$ or literature$ or studies or trial$ or effective$).ab.
  23. 20 and 22
  24. 21 adj10 22
  25. or/1-19,23,24
  26. editorial.pt.
  27. letter.pt.
  28. case study.pt.
  29. record review/
  30. peer review/
  31. (retrospective$ adj2 review$).tw.
  32. (case$ adj2 review$).tw.
  33. (record$ adj2 review$).tw.
  34. (patient$ adj2 review$).tw.
  35. (patient$ adj2 chart$).tw.
  36. (peer adj2 review$).tw.
  37. (chart$ adj2 review$).tw.
  38. (case$ adj2 report$).tw.
  39. exp case control studies/
  40. exp prospective studies/
  41. case studies/
  42. animal studies/
  43. “edit and review”/
  44. (rat$ or mouse or mice or hamster$ or animal$ or dog$ or cat$ or rabbit$ or bovine or sheep).tw.
  45. or/26-44
  46. 25 not 45

CINAHL (via Ebsco):

Click the text field below to select the filter text.