• YOPL

Ovid Medline Research Methodology Search Filters (and a couple of nifty limits)

Updated: Nov 19


Your search results are only as good as your search. Use a filter to separate the wheat from the chaff!


There will be a separate blog that covers subject oriented filters, such as vaccinations, age groups, etc. Stay tuned!


Be sure you take a look at the blog which gives an overview of search filters/search hedges. It can be found at: http://bit.ly/about-search-filters


As a reminder, we like to develop and run the subject content of the search strategy, then add the search filter and combine. Any additional limits, such as language or publication dates, would follow. Here is an example using the systematic review search filter:


This also shows the magic of using and. Line 3 returned over 444,500 citations; line 6 returned over 2.68 million! Combining them with and reduced the number to a little under 43,000. Adding in the search filter, then limiting by language and date returns a little over 1,700 citations for potential systematic reviews.


Following are research methodology search filters for the Ovid Medline database. You cannot use these in other databases unless you first adapt the vocabulary to the database and the syntax to the interface!


Systematic Reviews, Meta-Analysis, & Network Meta-analysis (updated August 26, 2021)

"systematic review".pt. or "Systematic Reviews as Topic"/ or "Cochrane Database of Systematic Reviews".jn. or (evidence report technology assessment or evidence report technology assessment summary).jn. or (((comprehensive* or integrative or mapping or rapid or realist or scoping or systematic or systematical or systematically OR systematicaly OR systematicly OR umbrella) adj3 (bibliographical or bibliographically or bibliographics or literature or review or reviews)) or (state adj3 art adj1 review) or (research adj2 synthesis) or ((data or information) adj3 synthesis)).ti,ab,kf. or ((data adj2 (extract or extracting or extractings or extraction or extraction).ti,ab,kf.) and ("review".ti. or "review".pt.)) or ((review adj3 (rationale or evidence)).ti,ab. and "review".pt.) or (cinahl or (cochrane adj3 (trial or trials)) or embase or medline or psyclit or (psycinfo not (psycinfo adj1 database)) or pubmed or scopus or (sociological adj1 abstracts) or (web adj2 science)).ab. or "Meta-Analysis".pt. or "meta-analysis as topic"/ or ((meta adj2 (analyse or analyser or analyses or analysis or analytic or analytical or analytics or analyze or analyzed or analyzes)) or metaanalyse or Metaanalysen or metaanalyser or metaanalyses or metaanalysis* or metaanalytic or metaanalytical or metaanalytics or metaanalyze or metaanalyzed or metaanalyzes).ti,ab,kf. or "network meta-analysis"/ or (network adj1 (meta or metaanalyses or metaanalysis or metaregression)).ti,ab,kf. or (((indirect adj3 (comparison or comparisons)) or ((mixed or multiple) adj1 (treatment or treatments))).ti,ab,kf. and ((meta adj2 (analyse or analyser or analyses or analysis or analytic or analytical or analytics or analyze or analyzed or analyzes)) or metaanalyse or Metaanalysen or metaanalyser or metaanalyses or metaanalysis* or metaanalytic or metaanalytical or metaanalytics or metaanalyze or metaanalyzed or metaanalyzes).ti,ab,kf.)


Just Cochrane reviews

"cochrane database of systematic reviews".jn.


Just Meta-Analysis & Network Meta-Analysis (updated August 26, 2021)

"Meta-Analysis".pt. or "meta-analysis as topic"/ or ((meta adj2 (analyse or analyser or analyses or analysis or analytic or analytical or analytics or analyze or analyzed or analyzes)) or metaanalyse or Metaanalysen or metaanalyser or metaanalyses or metaanalysis* or metaanalytic or metaanalytical or metaanalytics or metaanalyze or metaanalyzed or metaanalyzes).ti,ab,kf. or "network meta-analysis"/ or (network adj1 (meta or metaanalyses or metaanalysis or metaregression)).ti,ab,kf. or (((indirect adj3 (comparison or comparisons)) or ((mixed or multiple) adj1 (treatment or treatments))).ti,ab,kf. and ((meta adj2 (analyse or analyser or analyses or analysis or analytic or analytical or analytics or analyze or analyzed or analyzes)) or metaanalyse or Metaanalysen or metaanalyser or metaanalyses or metaanalysis* or metaanalytic or metaanalytical or metaanalytics or metaanalyze or metaanalyzed or metaanalyzes).ti,ab,kf.)


Just Meta-Analysis (NO Network Meta-Analysis) (updated August 26, 2021)

"Meta-Analysis".pt. or "meta-analysis as topic"/ or ((meta adj2 (analyse or analyser or analyses or analysis or analytic or analytical or analytics or analyze or analyzed or analyzes)) or metaanalyse or Metaanalysen or metaanalyser or metaanalyses or metaanalysis* or metaanalytic or metaanalytical or metaanalytics or metaanalyze or metaanalyzed or metaanalyzes).ti,ab,kf.


Just Network Meta-Analysis (updated August 26, 2021)

"network meta-analysis"/ or (network adj1 (meta or metaanalyses or metaanalysis or metaregression)).ti,ab,kf. or (((indirect adj3 (comparison or comparisons)) or ((mixed or multiple) adj1 (treatment or treatments))).ti,ab,kf. and ((meta adj2 (analyse or analyser or analyses or analysis or analytic or analytical or analytics or analyze or analyzed or analyzes)) or metaanalyse or Metaanalysen or metaanalyser or metaanalyses or metaanalysis* or metaanalytic or metaanalytical or metaanalytics or metaanalyze or metaanalyzed or metaanalyzes).ti,ab,kf.)


Publication type=Review

As a warning, not all systematic reviews have the publication type "review". This will find articles that have been indexed as general (i.e. narrative) reviews of the literature.

"review".pt.


Retractions, Withdrawals, Corrections, Comments, Replies to comments (October 28, 2021)

("retraction of publication".pt. or "Published Erratum".pt. or "comment".pt. or (comment or comments or correction or corrections or "expression of concern" or replies or reply or ((retraction or withdrawal) and (note or notice))).ti.)


Note: When completing a systematic review, use this search after article review and study selection but before coding. You will need to be creative as there is no consistency in how the record appears. EX: Consider doing a search with the author's name as well as a search with keywords from the title & abstract, then combine with OR to view the full list.

  1. wakefield aj.au. and ("retraction of publication".pt. or "Published Erratum".pt. or "comment".pt. or (comment or comments or correction or corrections or "expression of concern" or replies or reply or ((retraction or withdrawal) and (note or notice))).ti.)

  2. (((measles or mmr) and autism).ti,ab,kf. and autism.ti,ab,kf.) and ("retraction of publication".pt. or "Published Erratum".pt. or "comment".pt. or (comment or comments or correction or corrections or "expression of concern" or replies or reply or ((retraction or withdrawal) and (note or notice))).ti.)

  3. 1 or 2

Clinical trials (updated April 15, 2019)

("adaptive clinical trial" or "clinical trial" or "clinical trial, phase i" or "clinical trial, phase ii" or "clinical trial, phase iii" or "clinical trial, phase iv" or "controlled clinical trial" or "multicenter study" or "randomized controlled trial").pt. or double-blind method/ or "clinical trials as topic"/ or "clinical trials, phase i as topic"/ or "clinical trials, phase ii as topic"/ or "clinical trials, phase iii as topic"/ or "clinical trials, phase iv as topic"/ or "controlled clinical trials as topic"/ or "non-randomized controlled trials as topic"/ or "Equivalence Trials as Topic"/ or "Intention to Treat Analysis"/ or "Pragmatic Clinical Trials as Topic"/ or randomized controlled trials as topic/ or early termination of clinical trials as topic/ or multicenter studies as topic/ or ("phase I" or "phase II" or "phase III" or "phase IV" or "phase 1" or "phase 2" or "phase 3" or "phase 4").ti,ab,kf. or ((randomi?ed adj7 trial*) or (controlled adj3 trial*) or (clinical adj2 trial*) or ((single or doubl* or tripl* or treb*) and (blind* or mask*))).ti,ab,kf. or ("4 arm" or "four arm").ti,ab,kf.


Comparative studies (updated August 7, 2018)

This is a tough filter to do. The scope note from NLM for this study type is: “Comparison of outcomes, results, responses, etc for different techniques, therapeutic approaches or other inputs”; figuring out the right terms is complicated. Consider this a high-yield start to a search filter with probably a somewhat lower sensitivity (we're guessing ~80%) and higher specificity.

"comparative study".pt. or (comparative or "compared to" or comparing or comparison).ti,ab,kf.


Program evaluation (updated August 8, 2018)

evaluation studies/ or "evaluation studies as topic".pt. or program evaluation/ or validation studies/ or "validation studies as topic".pt. or (effectiveness or intervention or (pre- adj5 post-) or (pretest adj5 posttest) or (program* adj6 (evaluate or evaluated or evaluates or evaluating or evaluation or evaluations or evaluator or evaluators))).ti,ab,kf.


Epidemiologic Studies

NOTE: A word of caution for the next set of filters: Authors do not always use the appropriate terminology when describing their epidemiologic studies. This is true for the above as well, but we have noticed that the following study types are more frequently not identified as such in their titles or citations. Not only that, but a retrospective study can be a type of cohort study or it can be a type of case-control study! Use these filters with some caution. They will locate the kinds of study they should, but only when the author knows what kind of study they have done and has described it as such!


Case-control studies (reviewed October 28, 2021)

Case-Control Studies/ or Control Groups/ or Matched-Pair Analysis/ or ((case* adj5 control*) or (case adj3 comparison*) or (control adj1 group*)).ti,ab.


Cohort studies (updated August 6, 2018)

cohort studies/ or longitudinal studies/ or follow-up studies/ or prospective studies/ or retrospective studies/ or cohort.ti,ab,kf. or longitudinal.ti,ab,kf. or prospective.ti,ab,kf.


Cross sectional studies (updated November 26, 2018)

Cross-Sectional Studies/ or Prevalence/ or ((association adj2 (studies or study)) or cross-sectional or prevalence or transversal).ti,ab,kf. or (association or associations).ti.


The example below shows a search for sepsis and biomarker cross-sectional and association studies.



Incidence studies (updated August 8, 2018)

Incidence/ or (incidence or incidences).ti,ab,kf.


Prevalence studies (updated August 7, 2018)

Prevalence/ or cross-sectional studies/ or (prevalence or prevalences).ti,ab,kf.

Qualitative studies (updated October 5, 2020)

focus groups/ or interviews as topic/ or narration/ or qualitative research/ or (("face to face" or f2f or guided or depth or indepth or informal or semistructured or structured or unstructured) adj3 (discussion* or interview* or questionnaire*)).ti,ab,kf. or (ethnograph* or (field adj1 work) or fieldwork or (focus adj1 (group or groups)) or (key adj1 (informant or informants)) or qualitative).ti,ab,kf.


Guidelines/Recommendations (updated September 8, 2021)

(clinical protocols/ or Consensus/ or "Consensus Development Conference".pt. or "Consensus Development Conference, NIH".pt. or Consensus Development Conferences as Topic/ or Consensus Development Conferences, NIH as Topic/or critical pathway/ or guidelines as topic/ or practice guidelines as topic/ or Health Planning Guidelines/ or practice guideline/ or (clinical adj3 pathway).ti,ab,kf. or (clinical adj3 pathways).ti,ab,kf. or (practice adj3 parameter).ti,ab,kf. or (practice adj3 parameters).ti,ab,kf. or algorithms/ or (care adj2 pathway).ti,ab,kf. or (care adj2 pathways).ti,ab,kf. or guidance.ti,ab. or guideline*.ti.)


Limits using NOT-NOT

Limit to US studies (updated October 5, 2021)

Run your search as usual. Copy the statement below, being sure you fill in the last line number of your search before hitting Enter.

last-line-number not ((exp africa/ or exp asia/ or exp australia/ or exp canada/ or exp central america/ or exp europe/ or exp south america/) not (north america/ or exp united states/))


Limit to Human (updated April Oct. 5, 2021)

You can check a box to limit to human studies but here's the catch-- you are limiting to a MeSH term. The newest, most current citations do not have MeSH terms. Consequently, you are kicking out the most recent research by using the human limiter. The following method removes a significant number of animal studies (but not all) without removing human studies. See below "Limit by age groups" for an example.

last-line-number not (exp "Animals"/ not "Humans"/)


Limit by age groups (updated Oct. 5, 2021)

The following method removes a significant number of studies (but not all) by age groups-- but it won't be 100%.


Remove child and adolescent studies, keep adult studies

last-line-number not ((exp child/ or adolescent/) not exp adult/)


Remove child studies, keep adolescent and adult studies

last-line-number not (exp child/ not exp adult/)


Remove child, adolescent, and adult studies, keep infant studies

last-line-number not ((exp child/ or adolescent/ or exp adult/) not exp infant/)




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