Psychologists rely on both quantitative and quantitative research to better understand human thought and behavior. This article discusses what qualitative and quantitative research are, how they are different, and how they are used in psychology research.

Qualitative Research vs. Quantitative Research

In order to understand qualitative and quantitative psychology research, it can be helpful to look at the methods that are used and when each type is most appropriate. Psychologists rely on a few methods to measure behavior, attitudes, and feelings. These include:

Self-reports, like surveys or questionnairesObservation (often used in experiments or fieldwork)Implicit attitude tests that measure timing in responding to prompts

Most of these are quantitative methods. The result is a number that can be used to make assessments about differences between groups. However, most of these methods are static, inflexible (you can’t change a question because a participant doesn’t understand it), and provide a “what” answer rather than a “why” answer. Qualitative research is about speaking to people directly and hearing their words. It is grounded in the philosophy that the social world is ultimately unmeasurable, that no measure is truly ever “objective,” and that how humans make meaning is just as important as how much they score on a standardized test.

Quantitative Research Methods

Quantitative methods have existed ever since people have been able to count things. But it is only with the positivist philosophy of Auguste Comte (which maintains that factual knowledge obtained by observation is trustworthy) that it became a “scientific method.” The scientific method follows this general process. A researcher must:

Generate a theory or hypothesis (i.e., predict what might happen in an experiment) and determine the variables needed to answer their question Develop instruments to measure the phenomenon (such as a survey, a thermometer, etc.) Develop experiments to manipulate the variables Collect empirical (measured) data Analyze data

Quantitative research compares two groups of people. There are all sorts of variables you could measure, and many kinds of experiments to run using quantitative methods. These comparisons are generally explained using graphs, pie charts, and other visual representations that give the researcher a sense of how the various data points relate to one another. In some fields, these assumptions hold true. Whether you measure the size of the sun 2000 years ago or now, it will always be the same. But when it comes to human behavior, it is not so simple.

That the world is measurableThat humans can observe objectivelyThat we can know things for certain about the world from observation

As decades of cultural and social research have shown, people behave differently (and even think differently) based on historical context, cultural context, social context, and even identity-based contexts like gender, social class, or sexual orientation.

Statistics

Statistical information is the primary form of quantitative data used in human and social quantitative research. Statistics provide lots of information about tendencies across large groups of people, but they can never describe every case or every experience. In other words, there are always outliers.

Correlation and Causation

A basic principle of statistics is that correlation is not causation. Researchers can only claim a cause-and-effect relationship under certain conditions:

The study was a true experiment. The independent variable can be manipulated (for example, researchers cannot manipulate gender, but they can change the primer a study subject sees, such as a picture of nature or of a building). The dependent variable can be measured through a ratio or a scale.

So when you read a report that “gender was linked to” something (like a behavior or an attitude), remember that gender is NOT a cause of the behavior or attitude. There is an apparent relationship, but the true cause of the difference is hidden.

Pitfalls of Quantitative Research

Quantitative methods are one way to approach the measurement and understanding of human and social phenomena. But what’s missing from this picture? As noted above, statistics do not tell us about personal, individual experiences and meanings. While surveys can give a general idea, respondents have to choose between only a few responses. This can make it difficult to understand the subtleties of different experiences.

Qualitative Research Methods

Qualitative data are not made out of numbers but rather of descriptions, metaphors, symbols, quotes, analysis, concepts, and characteristics. This approach uses interviews, written texts, art, photos, and other materials to make sense of human experiences and to understand what these experiences mean to people. Qualitative methods are about describing and analyzing phenomena from a human perspective. There are many different philosophical views on qualitative methods, but in general, they agree that some questions are too complex or impossible to answer with standardized instruments. These methods also accept that it is impossible to be completely objective in observing phenomena. Researchers have their own thoughts, attitudes, experiences, and beliefs, and these always color how people interpret results.

Qualitative Approaches

There are many different approaches to qualitative research, with their own philosophical bases. Different approaches are best for different kinds of projects. For example:

Case studies and narrative studies are best for single individuals. These involve studying every aspect of a person’s life in great depth. Phenomenology aims to explain experiences. This type of work aims to describe and explore different events as they are consciously and subjectively experienced. Grounded theory develops models and describes processes. This approach allows researchers to construct a theory based on data that is collected, analyzed, and compared to reach new discoveries. Ethnography describes cultural groups. In this approach, researchers immerse themselves in a community or group in order to observe behavior.

Some researchers specialize in a single method, but others specialize in a topic or content area and use many different methods to explore the topic, providing different information and a variety of points of view.

Interpretation

Qualitative research does not look into causal relationships between variables, but rather into themes, values, interpretations, and meanings. As a rule, then, qualitative research is not generalizable (cannot be applied to people outside the research participants). The insights gained from qualitative research can extend to other groups with proper attention to specific historical and social contexts.

Relationship Between Qualitative and Quantitative Research

It might sound like quantitative and qualitative research do not play well together. They have different philosophies, different data, and different outputs. However, this could not be further from the truth. For example, a psychologist wanting to develop a new survey instrument about sexuality might and ask a few dozen people questions about their sexual experiences (this is qualitative research). This gives the researcher some information to begin developing questions for their survey (which is a quantitative method). After the survey, the same or other researchers might want to dig deeper into issues brought up by its data. Follow-up questions like “how does it feel when…?” or “what does this mean to you?” or “how did you experience this?” can only be answered by qualitative research.

A Word From Verywell

Qualitative and quantitative methods both play an important role in psychology. Where quantitative methods can help answer questions about what is happening in a group and to what degree, qualitative methods can dig deeper into the reasons behind why it is happening. By using both strategies, psychology researchers can learn more about human thought and behavior.