Quantitative Research is one of the two major research methodologies in health sciences. This research paradigm aims to precisely measure concepts, conditions, and theories through statistical analysis. Researchers gather data through structured interviews, questionnaires, close observational studies, document screening, and experiments to quantify patterns and relationships between variables within a population. 

Characteristics of Quantitative Research

  • Structured research instruments, such as controlled interviews and questionnaires to collect numerical data 
  • Results are based on large sample sizes that represent a population 
  • Study can be replicated or repeated, due to high reliability 
  • Method designed and intended to gather pertinent data 
  • Data appears in the form of numbers and statistical analysis, often presented in tables, charts, figures, and diagrams 
  • Research looks for patterns and relationships in generalized concepts 

While quantitative research strives to prove occurrences through numerical data, Qualitative Research, the other major research methodology, is "naturalistic", based on finding patterns or forming new theories through the research process. Qualitative research gathers data from a subject's lived experience, emotions, and behaviors, helping researchers gain a better understanding of complex problems, interactions and cultural phenomena. 

Characteristics of Qualitative Research:

  • Studies real world situations as they unfold, organically
  • The researcher is adaptable and avoids structured research instruments
  • Data is gathered through unstructured interviews and focus groups
  • More narrative, featuring actual experienced, more than statistical analysis 
  • Less generalized 
  • Observations take place on-site, sometimes role playing is involved 

Keyword searching is one way to locate quantitative and qualitative research. Besides methodology, use terms associated with the paradigms; for instance, if you're looking for quantitative literature, you may want to add terms like "data sets", "variables",  "statistics", "experimental" or "correlation" to your keyword searches. Each these of terms are commonly associated with quantitative research and will most likely produce meaningful results in both SearchUSA and in specific databases, like CINAHL or PubMed. One of the great benefits to keyword searching is that it allows the researcher to search multiple areas in any given bibliographic record, including the article's title, abstract, author supplied keywords, or subject headings.

    Subject Headings can also help you locate quantitative and qualitative literature. Databases like CINAHL and PubMed categorize records using subject terms or controlled vocabularies to speed up the search process. Often these terms are specific, technical and work alongside your keywords to give you more fruitful results. Subject headings, however, vary from database to database. PubMed, for instance, uses the National Library of Medicine's Medical Subject Headings (MeSH) to index information. Oddly, Quantitative research is not specifically indexed in PubMed, but numerous subject terms synonymous with quantitative research are, such as "Statistical Distributions", "Meta-Analysis as Topic", "Evaluation Studies", "Chi-Square Distribution" and many others.

    Filters & Limiters can help you hone your searches for quantitative and qualitative literature. Depending on the resource, filters and limiters, are usually located on the left-hand side of the results page. What's great about filters and limiters is that you can sharpen your search as you browse articles.  In PubMed, you can filter results by "Article Type" (see video in "Sample Searches") and select the types of articles you want to view, such "Case reports" (qualitative research) or "Clinical trials" (quantitative research).

    Another great tool in the filter category is the "Subject" filter which can be utlized to locate controlled vocabulary to strengthen keyword searches in SearchUSA and in quite a few databases.


    Here are a few helpful keywords to help jump-start your searches: 

     Quantitative research

    • Correlation
    • Data 
    • Distribution 
    • Experiments 
    • Pre-test/post-test  
    • Randomized Controlled Trials 

     Qualitative research

    • Case studies 
    • Ethnographic 
    • Focus groups 
    • Interview 
    • Narrative 
    • Phenomenological 
    Finding Quantitative & Qualitative Literature
    Using SearchUSA to Locate Qualitative Research

    Using PubMed to Locate Quantitative Research