These strategies can help you locate qualitative and quantitative articles as you search library databases. For biomedical research, we recommend you begin from the ADVANCED SEARCH page in research databases.
Limit your searches to Peer Reviewed articles. (This strategy will provide you with the most results.) Research studies that use qualitative and quantitative methods are published in peer reviewed journals. Not every article in a peer reviewed journal will be a research study, but limiting your results to articles in these journals will help you narrow the pool of articles you are looking through.
Databases use controlled keywords (known as thesaurus or subject terms) to categorize each record stored. PubMed and MEDLINE, for example, both use Medical Subject Headings (MeSH), a highly structured index of terminology. The subject headings vary for each database according to their indexing system. The term "qualitative research" is indexed in PubMed as "Qualitative Research" or "Nursing Methodology Research", while in CINAHL the subject heading "Qualitative Studies" is complemented by more detailed terms, including "Phenomenological Research" and "Grounded Theory." See next tabs for more detailed information on finding articles in specific databases.
The video below explains how to use MeSH in CINAHL, but the basic principle applies to searching by subject heading in MEDLINE and PubMed.
Limit to Research Articles and/or Peer-Reviewed Journals. Limit your results to publication types that are quantitative or quantitative by definition. For quantitative, look for things like Meta-analysis, Clinical Trial, Statistics, Tables/Charts, etc. For qualitative, look for publication types such as Anecdote, Interview, Metasynthesis, etc.
This strategy uses text that might specifically identify the type of research you're seeking. These keywords will be used to search the titles, abstracts and keywords of records held in the databases.
For Qualitative Research, some keywords include: qualitative, ethnograph*, phenomenol*, ethnonurs*, grounded theor*, purposive sample, hermeneutic*, heuristic*, semiotics, lived experience*, narrative*, life experiences, cluster sample, action research, observational method, content analysis, thematic analysis, constant comparative method, field stud*, theoretical sample, discourse analysis, focus group*, ethnological research, ethnomethodolog*, interview*.
For Quantitative Research, use keywords that might specifically identify quantitative research and that search the titles, abstracts, and keywords of records held in the databases. Some keywords include: Correlational design*, Effect size, Empirical research, Experiment*, Hypothesis, Quasi-experiment*, Reliability, Sampl*, Validity, Variables, Chi Square Test, Analysis of Varience, Confidence intervals, Statistic*.
Search filters are pre-tested strategies that identify the higher quality evidence from the vast amounts of literature indexed in the major medical databases. Filters exist for most types of experimental design, and are comprised of index terms relating to study type and specific terms associated with the methodological description of good experimental design. You can use the filter and then combine the results with your subject.
It is important when searching databases which have a thesaurus and which tag articles with subject headings (Medline, CINAHL, etc.) that your search strategy combines (with OR) both relevant subject headings and keyword/free-text searches on a particular concept.
It helps to know about the different sorts of evidence used in healthcare research--knowing what is defined as a filtered vs. unfiltered research study will help provide context for understanding Quantitative and Qualitative research.
Scholarly journals contain many types of articles. Here are some of the different formats you may see, and some of their defining characteristics:
Review articles (AKA filtered information: includes literature reviews, systematic reviews, meta-analyses):
Primary research articles (unfiltered information: research studies, reports, clinical reports):
Case studies (unfiltered information: includes case reports)