Researchers generally choose one of two approaches to gathering evidence for their projects: qualitative or quantitative methods. Qualitative approaches focus on achieving understanding from an in-depth or close-up perspective. Quantitative methods tend to gather responses and data from a larger number of participants and from surveys. Qualitative and quantitative approaches both have benefits and limitations, depending on the type of research project in question.
Quantitative Methods Defined
Quantitative approaches usually involve gathering data through very structured research instruments, such as surveys distributed to large numbers of participants to represent an entire population. The research question needs to be precisely defined and geared to objective answers. Quantitative research is rooted in numbers and statistics, with results often represented in tables, charts or graphs.
The results can typically be generalized more broadly to predict or further examine cause and effect. One strength of quantitative methods is the avoidance of personal researcher bias through numerical techniques. Yet, a quantitative approach tends to lack flexibility due to rigid data-collection methods.
Qualitative Methods Defined
In contrast to quantitative approaches, qualitative research methods are less driven by hard data. They include in-depth interviews, focus groups and open-ended questions to increase understanding of a phenomenon. A smaller number of participants is typical, with open-ended questions allowing interviewers to understand the experiences of their participants in greater depth. Sometimes the verbal information gathered can be converted to numbers, but qualitative research is more anecdotal than quantitative approaches.
A key strength of qualitative research is the ability it offers researchers to penetrate the masks and defenses of interviewees, to discover meanings and to reveal the complexities of social issues and problems. On the other hand, qualitative research demands a great deal of researchers' time and effort, and results can be confusing to interpret.
Quantitative research methods are based on anything that can be measured with precision, such as the cause-and-effect relationship between a hummingbird's wing beats per minute and heart rate. While quantitative research focuses on a single aspect of reality that can be measured precisely, qualitative research attempts to describe shifting and multiple realities that are rooted in individual interpretation.
Though qualitative research delves into phenomena that can't be measured with precision, such as employee job satisfaction, numerical and statistical data may be employed; however, although a specific percentage of participants might indicate satisfaction with their jobs, it's impossible to translate that to a numerical scale that measures satisfaction precisely.
When to Use Them
Qualitative methods are best for when researchers want to make discoveries about changing realities. Quantitative methods are good for comparing data or statistics systematically and testing theories or make generalizations about an entire population. A researcher interested in exploring how children use video games may approach the project with qualitative methods in mind, because interviews mixed with observation of the children are more likely to yield insights. In contrast, a study of the effects of crossed legs on blood pressure readings requires quantitative methods.
- The Chronicle of Evidence-Based Mentoring: On Methods: What's the Difference Between Qualitative and Quantitative Approaches?
- University of Southern California Libraries: Quantitative Methods
- University of Plymouth: Qualitative Research
- University of Wisconsin at Madison, Ebling Library: Differences Between Qualitative and Quantitative Research
- The London School of Economics and Political Science: FAQ 1: When Is It Better to Do Qualitative or Quantitative Research?
- AndreyPopov/iStock/Getty Images