Differences between quantitative and qualitative research

In quantitative research, the outcome of your research is numerical data or statistics. In qualitative research, the results consist of opinions, ideas, or observations. You do not collect numerical information. What exactly are the differences between quantitative and qualitative research? When do you choose to use each type of research? We will explain it to you.

The difference between quantitative and qualitative research is in the type of data you collect.

In quantitative research, you collect data that can be expressed in numbers, percentages, or statistics. With quantitative research, you test hypotheses or theories in order to confirm or disprove them. For quantitative data, you often collect data from a large sample, so you can generalize the findings to an even larger group. You usually use methods such as an experiment or surveys with closed-ended or multiple-choice questions for this purpose. 

In qualitative research, you are more likely to express the data you collect in words. You use this type of research to gain a better understanding of certain behaviors, ideas, or concepts. Often this type of research is appropriate when relatively little isknown about your topic or about a particular case. Methods you can use for this type of research include observations, interviews, focus groups, or a literature review. Case studies are also common.

Here are the main differences between these methods:

Not only does the type of data you collect differ between qualitative and quantitative research, the method of data collection does too.

Different research methods are appropriate for both types of research. 

Incidentally, some data collection methods are useful for both qualitative and quantitative research. For example, interviews are sometimes qualitative (open-ended questions to get a broad view of a particular topic) and sometimes quantitative (closed-ended questions to gather numerical information).

The following research methods are common in quantitative research:

• Experiment: in an artificial setting, you manipulate certain variables in order to investigate a causal relationship between them.

• Surveys: you present  people with a list of closed-ended or multiple-choice questions to answer. 

• Quantitative observations: you count the number of times certain behaviors, phenomena or statements occur. 

These are examples of methods for qualitative data collection:

• Case study: you do extensive research on one or a number of specific cases and explore them in great detail. 

• Interviews: you ask respondents open-ended questions to hear their detailed opinions on a particular topic.

• Focus group: you bring a group of respondents together to discuss their answers to certain questions about your topic. This way, you gain insight into their ideas, opinions, and/or behavior. 

• Literature review: you analyze a large number of previous studies on your topic to answer your research question.

We discuss an example below to show the differences between quantitative and qualitative research. 

Your research question is "How do eighteen-year-olds in the Netherlands view eating fruit?". You can research this with either a quantitative or qualitative approach. A mixed methods study (a research approach in which you combine quantitative and qualitative methods) is also possible. 

Example: quantitative research

For a quantitative approach, you can think of a survey-based study. You have 500 eighteen-year-olds fill out a survey with closed questions about eating fruit. Think of statements where respondents indicate where their opinion regarding certain statements falls on a scale from "totally disagree" to "totally agree.” You also ask respondents how much fruit they eat. That way, you can draw quantitative conclusions from their answers. For example, you can calculate averages and reference percentages when discussing the findings. 

Example: qualitative research

In qualitative research, you conduct research with a smaller number of respondents and explore their views on fruit eating more extensively. For example, you put together three focus groups of five students each and ask them for their opinions on eating fruit. In these groups, you ask open-ended questions such as "What makes it difficult for you to eat fruit?" or "To what extent do you think eating fruit is important?".

Example: mixed methods

In "mixed methods" research, you can combine a quantitative survey distributed to a large number of eighteen-year-olds with a focus group where you go into more depth with a few people’s opinions. 

For example, you might first do survey research to get a broad picture of how much fruit this group eats and what challenges they might be facing. Then, you start trying to explain that data by talking about it with a select group of eighteen-year-olds and asking them questions based on your previous findings.

This article discusses in detail the differences between quantitative and qualitative research. This will help you make better choices about your research design. Will you soon be done doing your research? Be sure to come back to our knowledge base to find tips for writing your thesis and writing the method chapter. That way, you can be sure that your research will also look good on paper.