Differences Between Qualitative and Quantitative Research

What are qualitative and quantitative research methods^1,2

While conducting research for a study, authors undertake different types of research methods depending on their research question and the study type. These research methods are of two types—qualitative and quantitative.

Qualitative research is the process of collecting, analyzing, and interpreting non-numerical data. This method uses reasoning and focuses on the validity rather than the reliability of the results. The observations of this research are expressed in words and help in understanding individuals’ subjective perception about an event, condition, or subject. This type of research is exploratory and is used to generate hypotheses or theories from data. Qualitative data are non-numerical, in the forms of text, videos, photographs, and audio recordings.

Quantitative research is the process of collecting and analyzing numerical data to describe, predict, and control the variables of interest. The results are expressed in numbers and graphs and help in testing the causal relationships between variables, making predictions, and generalizing results. This research is used for testing a theory and then approving or rejecting it based on the results.

Before starting their research process, researchers should understand the different types of research methods to decide the best method for their study type. Most studies use either the quantitative or qualitative method, but in some cases a mixed methods approach may be more useful.

Differences between qualitative and quantitative research¹

The following table lists a few important differences between qualitative and quantitative research.

Data collection methods³

Qualitative research

1. Interviews: This helps understand a respondent’s subjective opinion and experience pertaining to a specific topic or event. Semi-structured interviews, which have open-ended questions (where the respondents can answer more than just “yes” or “no”), are commonly used.
2. Document study/Literature review: Researchers’ review of written materials such as archives, annual reports, research articles, guidelines, policy documents, etc.
3. Focus groups: Usually include a small sample of about 6-8 people and a moderator, to understand the participants’ opinion on a given topic.
4. Ethnography: Data are collected through observations and interviews and then analyzed to understand how society and individuals function.

Quantitative research

1. Controlled observations: These are observations made under standard and systematic conditions rather than casual or incidental conditions.⁴ They are conducted in a closed space where the researcher decides the participants and conditions under which the observations will be carried out.
2. Interviews/surveys: These interviews are structured and restricted to closed-ended questions where the respondents must strictly respond with a “yes” or “no” answer. Alternatively, a rating scale may be provided from which the respondents would need to choose a specific rating.

The quantitative data collection methods can be of the following designs⁵:

• Experimental—examines cause and effect
• Quasi-experimental—examines cause; used when not all variables can be controlled
• Descriptive—examines characteristics of a particular situation or group
• Correlational—examines relationships between two or more variables

Quantitative research vs Qualitative research¹

A few advantages and disadvantages of each research method are listed in the table below.

When to use qualitative, quantitative, or mixed methods

The type of research method to be selected depends on a few important criteria:

• Research question and study type
• Miscellaneous: time, costs, data availability, availability of respondents

You could follow this simple rule of thumb:

Objective: To validate or test a theory or hypothesis => Method: Quantitative research

Objective: To understand a topic/event or identify reasons for observed patterns => Method: Qualitative research

A mixed methods approach draws on the strengths of both quantitative and qualitative research in the same study. This method allows researchers to corroborate their findings, verify if the results observed using both methods are complementary, and explain any unexpected results obtained from one method by the other method.³ However, do note that this method could be more effort- and cost-intensive because of the requirement of more resources. The figure above⁶ shows some basic mixed methods research designs that could be used.

To conclude, both quantitative and qualitative research methods comprise several constituent data collection and analysis methods, any of which could be used depending on the study type. We hope that this article has provided an insight into the differences between qualitative and quantitative research so that you could efficiently decide on the most appropriate method for your study.

References

1. McLeod, S. A. Qualitative vs. quantitative research. Simply Psychology, (July 30, 2019). www.simplypsychology.org/qualitative-quantitative.html.
2. American Medical Association. AMA Manual of Style. Section 19: Study design and statistics
3. Busetto L., Wick W., Gumbinger C. How to use and assess qualitative research methods. Neurological Research and Practice [Accessed October 12, 2022] https://neurolrespract.biomedcentral.com/articles/10.1186/s42466-020-00059-z
4. APA dictionary of psychology [Accessed October 17, 2022] https://dictionary.apa.org/controlled-observation
5. Wilson B., Austria M-J, Casucci T. Understanding quantitative and qualitative approaches. University of Utah Health [Accessed October 15, 2022] https://accelerate.uofuhealth.utah.edu/improvement/understanding-qualitative-and-quantitative-approac
6. Mixed methods research. Community Engagement Program. Harvard Catalyst [Accessed October 17, 2022] https://catalyst.harvard.edu/community-engagement/mmr