A Primer to Experimental and Nonexperimental Quantitative Research: The Example Case of Tobacco-Related Mouth Cancer

To present a comprehensive overview of key constructs of experimental and nonexperimental quantitative research, drawing on one example case from cancer care.

Published scientific articles, research textbooks, and expert advice were used in this article.

Quantitative research turns information collected about people or about processes into numerical data. Depending on the underlying purpose, the goal is to address questions that have to do with intervention, prognosis, causation, association, description, or assessment. In experimental research, an intervention is manipulated. True experimental research (randomized controlled trial) controls confounding variables via use of both randomization and a control group; quasi-experimental research misses one or both of these elements. In either case, the aim is to generate evidence to confidently say that an intervention is the true cause of an observed outcome. Nonexperimental research is multifaceted. Cohorts and case-control studies can be used to test cause-and-effect relationships where experimental research is unethical or impractical. Correlational research aims to explore possible associations (exploratory) or help anticipate outcomes (predictive) and, quite often, is the precursor of experimental research. Descriptive research (simple, comparative, survey, retrospective chart review) can be used to describe and assess situations, conditions, or behaviors.

Understanding the different aims and goals of the different types of quantitative research can help increase capacity and confidence in understanding, appraising, and applying quantitative evidence among health care students, professionals, and novice researchers in the quest for the provision of quality cancer care.