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Ovid Medline Search Filters

Clinical trials

Clinical trials (updated 29 August 2024)

Note: This includes articles about the practice of trials as well as articles in which the study methodology is some type of trial.

(("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 "equivalence trial" or "multicenter study" or "pragmatic clinical trial" or "randomized controlled trial").pt. or "adaptive clinical trials as topic"/ or "Clinical Studies as Topic"/ 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 "double-blind method"/ or "early termination of clinical trials"/ or "equivalence trials as topic"/ or "intention to treat analysis"/ or "multicenter studies as topic"/ or "non-randomized controlled trials as topic"/ or "pragmatic clinical trials as topic"/ or "randomized controlled trials as topic"/ or (("2" or two or "3" or three or "4" or four) adj arm).ti,ab,kf,kw. or ((clinical or controlled or (cross adj over) or crossover or equivalent or pragmatic or randomisation or randomised or randomization or randomized) adj3 (studies or study or trial or trials)).ti,ab,kf,kw. or (cluster* adj3 (randomised or randomized)).ti,ab,kf,kw. or (stepped adj wedge).ti,ab,kf,kw. or ((window adj opportunity) and trial).ti,ab,kf,kw. or (phase adj1 ("I" or "II" or "III" or "IV" or "1" or "2" or "3" or "4")).ti,ab,kf,kw. or ((one or two or three or four or single or doubl* or tripl*) adj4 (blind or blinded or mask or masked)).ti,ab,kf,kw. or (intervention or interventions).ti.)

CTs with *many* Animals & plants studies removed

Remove plant and animal studies  (updated 29 August 2024)

  • It's not possible to remove all plant and animal studies using the NOT-NOT filter at the end of the search statement, but it will remove a significant number of them. Also, as you add other terms/concepts to the search, more of the non-relevant results will be removed.

(("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 "equivalence trial" or "multicenter study" or "pragmatic clinical trial" or "randomized controlled trial").pt. or "adaptive clinical trials as topic"/ or "Clinical Studies as Topic"/ 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 "double-blind method"/ or "early termination of clinical trials"/ or "equivalence trials as topic"/ or "intention to treat analysis"/ or "multicenter studies as topic"/ or "non-randomized controlled trials as topic"/ or "pragmatic clinical trials as topic"/ or "randomized controlled trials as topic"/ or (("2" or two or "3" or three or "4" or four) adj arm).ti,ab,kf,kw. or ((clinical or controlled or (cross adj over) or crossover or equivalent or pragmatic or randomisation or randomised or randomization or randomized) adj3 (studies or study or trial or trials)).ti,ab,kf,kw. or (cluster* adj3 (randomised or randomized)).ti,ab,kf,kw. or (stepped adj wedge).ti,ab,kf,kw. or ((window adj opportunity) and trial).ti,ab,kf,kw. or (phase adj1 ("I" or "II" or "III" or "IV" or "1" or "2" or "3" or "4")).ti,ab,kf,kw. or ((one or two or three or four or single or doubl* or tripl*) adj4 (blind or blinded or mask or masked)).ti,ab,kf,kw. or (intervention or interventions).ti.) not ((exp animals/ or exp plants/) not humans/)

Other experimental & quasi-experimental study types

Terms for non-randomized trials/quasi-experimental (Updated 13 May 2024)

To guide vocabulary development, I used the following article:

  • Harris AD, McGregor JC, Perencevich EN, Furuno JP, Zhu J, Peterson DE, Finkelstein J. The use and interpretation of quasi-experimental studies in medical informatics. J Am Med Inform Assoc. 2006 Jan-Feb;13(1):16-23. doi: 10.1197/jamia.M1749. Epub 2005 Oct 12. PMID: 16221933; PMCID: PMC1380192.

"Controlled Before-After Studies"/ or "Interrupted Time Series Analysis"/ or ((interrupted adj time) or (non adj (randomised or randomized)) or nonequivalent or nonrandomised or nonrandomized).ti,ab,kf,kw. or ((one adj group) and (((post or pre) adj test) or pretest or posttest)).ti,ab,kf,kw. or (((pretest or (pre adj5 (intervention or posttest or test))) and (posttest or (post adj5 (intervention or test)))) or (pretest adj5 posttest) or quasiexperimental or (quasi adj experimental) or ((single adj group) and (group adj study)) or (uncontrolled adj (studies or study))).ti,ab,kf,kw. or intervention.ti.


Comparative studies (Updated 14 October 2024)

NLM scope note:

  • “Comparison of outcomes, results, responses, etc for different techniques, therapeutic approaches or other inputs”

One could argue that clinical trials, by definition, are comparative studies, even if the comparison is against a placebo or sham, so 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. Also note that comparative studies can be experimental or not.

There are currently 2 versions as we continue testing:

Limit to trials: reduces the number of observational studies

Includes quasi-experimental studies

("comparative study".pt. or (comparative or comparing or (comparison adj (between or "of")) or versus or vs).ti. or ((comparative adj2 (analysis or outcome or outcomes or "study")) or (compared adj ("to" or "with")) or (superiority adj2 analysis)).ti,ab,kf,kw.) and ((nonrandomised or nonrandomized or (quasi adj experimental) or randomised or randomized).ti,ab,kf,kw. or (trial OR trials).ti.)

No limiting to trials: much broader

"comparative study".pt. or (comparative or comparing or (comparison adj (between or "of")) or versus or vs).ti. or ((comparative adj2 (analysis or outcome or outcomes or "study")) or (compared adj ("to" or "with")) or (superiority adj2 analysis)).ti,ab,kf,kw.


Evaluation studies (Updated 13 May 2024)

Includes quasi-experimental/non-randomized and randomized trials, interventions, programs, etc.

"evaluation study".pt or "evaluation studies as topic"/ or program evaluation/ or "reproducibility of results"/ or "validation study".pt. or "validation studies as topic"/ or (((pre adj5 test) and (post adj5 test)) or (pretest adj5 posttest) or ((intervention or nonrandomized or program* or (quasi adj1 experimental) or randomised or randomized) adj5 (effectiveness or evaluate or evaluated or evaluates or evaluating or evaluation or evaluations or evaluator or evaluators or reliability or reproducibility or validity))).ti,ab,kf,kw.


Quality improvement (Updated 13 May 2024)

QI studies are hard to categorize as some will be randomized trials, some are pre-post studies, and some are continuous improvement projects. The article below describes the life cycle of a QI project.

  • Likosky DS. Developing and executing quality improvement projects (concept, methods, and evaluation). J Extra Corpor Technol. 2014 Mar;46(1):38-44. PMID: 24779118; PMCID: PMC4557509.

("Quality Improvement"/ or ((implementation adj1 "research") or ((assurance or improve or improvement or improvements or improving or indicator or indicators or measure or measures or metric or metrics) adj1 quality) or ((improvement or pay) adj2 performance) or (knowledge adj2 translation) or (lean adj2 (methodology or principles or tools)) or (rapid adj1 cycle adj1 (change or changes)) or (report adj1 (card or cards)) or (right adj1 care) or (six adj1 sigma) or squire).ti,ab,kf,kw.)