Given their differences, it may come as no surprise that quantitative and qualitative research in psychology and related fields do not coexist in complete harmony. Some quantitative researchers criticize qualitative methods on the grounds that they lack objectivity, are difficult to evaluate in terms of reliability and validity, and do not allow generalization to people or situations other than those actually studied. At the same time, some qualitative researchers criticize quantitative methods on the grounds that they overlook the richness of human behavior and experiences and instead answer simple questions about easily quantifiable variables.

Some researchers agree that quantitative and qualitative approaches can and should be combined into what has come to be called mixed-methods research (Todd et al., 2004). One approach is to conduct a qualitative study first and then use the results for hypothesis generation and testing in a follow-up quantitative study. A second approach for combining quantitative and qualitative research is called triangulation, where researchers use both quantitative and qualitative methods simultaneously to study the same general questions and to compare the results. If the results of the quantitative and qualitative methods come to the same general conclusion, they reinforce and enrich each other. Using qualitative research can often help clarify quantitative results. For example, Trenor and colleagues investigated the university experiences of female engineering students. In the first phase, female engineering students completed a survey, where they assessed their perceptions of the University, including their sense of belonging. Statistically, the various ethnic groups showed no differences in their ratings of sense of belonging. One might conclude from these data that ethnicity does not have anything to do with sense of belonging to a college or university. However, in the second phase of their study, the authors also conducted interviews with the students, in which many minority students reported how diversity at the university enhanced their sense of belonging (Trenor et al., 2008). Without the qualitative component, they might have drawn the wrong conclusion about the quantitative results.

There are two other important types of research study that we want to discuss in this section, they are Case Studies and Participatory Action Research. Both often use qualitative and quantitative data.

Case Studies

Case studies are detailed, often lengthy studies of a very small number of individuals (sometimes as few as only one). Case studies have been used throughout the history of psychology to better understand the mind and behavior. For example, Sigmund Freud developed psychoanalytical theory based on case studies of his patients. Case studies are frequently used in clinical psychology to better understand psychological and neurological disorders. One downside of case studies is that we do not know how generalizable the findings are to the general population, because only small numbers of participants are studied.

Participatory Action Research

Participatory Action Research (PAR) is a research framework that aims to bring about social change. The research is guided by the needs and desires of community members who are grappling with specific social justice issues in their community. Community members work in collaboration with academic researchers as partners in a research team. Unlike most other kinds of research study in psychology, community members are active participants in all stages of PAR projects. PAR projects not only provide information about a community issue, but they also result in some kind of action designed to bring about improvements (Carleton College, n.d.; Fine & Torre, 2019). An example of PAR includes the Morris Justice Project. Maria Elena Torre and Brett Stoudt, two scholar-activists from City University of New York (CUNY) collaborated with community members in the Morris Avenue area of the Bronx to document the experiences and impact of aggressive policing on the community. This area had particularly high rates of “stop and frisk” of young Black men. Together they formulated a research plan, and community members surveyed over 1000 people in the neighborhood. They disseminated this information in multiple formats, including a report, buttons, and t-shirts, and at various community events. The project was successful in raising awareness of the problem among multiple groups, including the NYPD and people who lived in other neighborhoods. It was also used to support legal action against police officers, and recent legislation (Safer Communities Act, 2022) to protect people of color from discriminatory police practices.