In general, quantitative research seeks to understand the causal or correlational relationship between variables through testing hypotheses, whereas qualitative research seeks to understand a phenomenon within a real-world context through the use of interviews and observation.
Both types of research are valid, and certain research topics are better suited to one approach or the other. However, it is important to understand the differences between qualitative and quantitative research so that you will be able to conduct an informed critique and analysis of any articles that you read, because you will understand the different advantages, disadvantages, and influencing factors for each approach.
The table below illustrates the main differences between qualitative and quantitative research. Be aware that these are generalizations, and that not every research study or article will fit neatly into these categories.
|Keywords||Complexity, contextual, inductive logic, discovery, exploration||Experiment, random assignment, independent/dependent variable, causal/correlational, validity, deductive logic|
|Purpose||Understand a phenomenon||Discover causal relationships or describe a phenomenon|
|Sample||Purpose sample, small||Random sample, large|
|Data||Focus groups, interviews, field observation||Tests, surveys, questionnaires|
|Methods/Design||Phenomenological, grounded theory, ethnographic, case study, historical/narrative research, participatory, research, clinical research||Experimental, quasi-experimental, descriptive, methodical, exploratory, comparative, correlational, developmental (cross-sectional, longitudinal/prospective/cohort, retrospective/ex post facto/case control)|
Systematic reviews, meta-analyses, and integrative reviews are not exactly designs, but they synthesize, analyze, and compare the results from many research studies and are somewhat quantitative in nature. However, they are not truly quantitative or qualitative studies.
LoBiondo-Wood, G., & Haber, J. (2010). Nursing research: Methods and critical appraisal for evidence-based practice (7th ed.). St. Louis, MO: Mosby Elsevier
Mertens, D. M. (2010). Research and evaluation in education and psychology (3rd ed.). Los Angeles: SAGE
Adapted from Stevenson University's "Qualitative vs. Quantitative Research: Overview"