There seems to be some confusion about the differences between Research Design and a Research Method. As Ph.D researchers, we may focus too much on how we will collect and analyze our data, and not give enough time to understanding what our research is trying to accomplish. Having a clear understanding of what our research design is will help inform us about the best research methods to use.

Research designs and research methods are interconnected parts of research, but they play different roles in the research process.

Research design - a well-structured plan for the entire research process that defines:

The research topic,
The research purpose or problem statement (problem, puzzle, or gap that exists in your field),
The research scope,
The research question(s),
The type of study best suited to answer the research question(s),
The research methods,
The expected outcomes of our research (the implications of our expected findings)

Your research problem or research questions determine what type of study you should conduct, and the type of study informs what research methods are best suited to your research.

Type of study is important to define in your research design, because not all research is conducted in the same manner. We are probably familiar with the three broad types of research:

Under each type of study, we can further define our research design. The three links above (Quantitative, Qualitative, Mixed-Method) provide examples of various research designs for each type of study. Knowing your research design in more detail can help you make more informed decisions about the research methods you will use and the type of research you will actually produce in your Ph.D.

For example, an experimental study is a common type of quantitative study, and applies a hypothesis to address a research question or problem statement. The research methods will vary depending on the type of experiment and variables being tested.
A systematic literature review can be a type of qualitative study if the research method is discourse analysis.

Research methods are different than a research design and type of study. Research methods are:

the tools, procedures and approaches used to gather and analyze data required to answer your research question(s)
defined by the type of study you will use and influenced by the research design

Research methods must conform to the type of question(s) you are asking, the type of study you are conducting, and the research design best suited to answer your research question. Defining your type of study and research design is therefore vital to complete before beginning your data collection - a well-defined research design will inform you about what data is necessary to collect, the best methods to collect the data, and helps position your research address your research purpose (the problem, puzzle, or gap in your field).

The University of Southern California Library Guide provides an overview of various research designs, their benefits, and their limitations. We advice you review the link to understand which research design is best for your research. The Guide offers more information on the following research designs:

Action research design
Case study design
Causal design
Cohort design
Cross-sectional design
Descriptive design
Experimental design
Exploratory design
Field research design
Historical design
Longitudinal design
Meta-analysis design
Mixed-method design
Observational design
Philosophical design
Sequential design
Systematic review

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