The two types of research including quantitative and qualitative refers to the type of data used in the research. Generally, if the data is numerical, it is quantitative. Otherwise, it is qualitative.
Qualitative research
With this in mind, it is obvious that qualitative researches usually study human behavior and other phenomena which is not measurable. It helps to develop ideas or hypotheses. The parallel researches for this kind of research can be empirical, exploratory, investigative, case studies, and subjective research.
Research questions
The research questions are often “how” and “why” something happens. It can establish cause and effect relationships.
Methodology
The methods of data collection could be interview, observation, or documents (including books, papers, and so on). So the qualitative methods use unstructured or semi-structured techniques.
Data analysis and results
In order to analyze data, the data should be described, compared, and the results reported. Qualitative researches aim for discovering patterns or possible links between variables.
Quantitative research
Quantitative researches study the facts, science, and society. Quantitative research mostly is experimental like applied behavioral analysis, and non-experimental like surveys, causal-comparative and correlational researches.
Quantitative researches are objective because they use numerical data which relates to mathematics that is an objective science, and because of this characteristic, the results will be generalizable.
Quantitative researches are useful for testing and validating theories constructed through qualitative researches.
Research questions
Quantitative research tries to solve
Methodology
The methods of data collection are using questionnaires, controlled observations, and other measurable methods. So the data is numerical or can be transported into statistics. For example, it can be put into categories. It is more structured than qualitative research data.
In order to conduct quantitative research, you need a sample which needs to be of a large size so that the research be reliable.
Data analysis and results
Since the data are in numerical form, it can be analyzed by statistical methods and software and the results can be reported in the form of graphs, tables, etc. as well as a description of them.
The mixed method
Today using the combination of qualitative and quantitative researches is increasing. In fact, these two kinds of research are not opposite, but they are of two different philosophies.
In research that combines the two types of researches, the elements of both can be used. The results also is a combination of why and what. So you can gain much deeper insights.
The uses of mixed method
Mixed method is useful especially for market researches. Since when you interview with people (qualitative research) you can be aware of their emotional, the lacks they feel your product/ service has, etc. while, with the help of a questionnaire (quantitative research) you have a statistical and exact result of your customers’ satisfaction.
The following table has been borrowed from “Research Design” book by “Creswell” which compares the three approaches:
