Quantitative and Qualitative methodologies

Research methodologies can be broadly defined into three approaches: quantitative, qualitative and mixed methods (both). Traditionally, quantitative methodologies are the reserve of the sciences, where repeatable, controlled experiments are preferred. Conversely, qualitative methodologies have been associated with the social sciences, where research is a bit more nuanced. The reality is that both approaches are useful in different contexts, and understanding how and when to use them is important when gathering information about your system.

Example applications

Quantitative methodologies explore measurable trends, such as the data gathered in an experiment or in a survey. Quantitative approaches look for relationships between variables.

Qualitative methodologies explore phenomena that are harder to measure. Examples include narrative research, phenomenological research, grounded theory, ethnography and case studies.

Mixed methods explore a problem using both methodologies. For example, a survey might use mixed methods if it includes open-ended questions, or if observational data is quantified and generalised to a broader context.

Steps

To decide what approach your research might employ, you should have a clear idea of your research question (see R01), and what data might already be available. Creswell (2003, p19) suggests this rule of thumb:

• Quantitative approaches use closed-ended questions, predetermined approaches and numerical data
• Qualitative approaches use open-ended questions, emerging approaches, text or image data
• Mixed methods use open- and closed-ended questions, emerging and predetermined approaches, and both quantitative and qualitative data

Key concepts

• an overview of the key differences between the three research methodologies
• a practical example of each research methodology in the context of your DLab theme
• advice to the student engineer on how to select a research methodology given the data or approach that might be used

Core resources

• Creswell, J.W., 2003, Research Design: Qualitative, Quantitative and Mixed Methods Approaches, Sage Publishing (particularly p18-21) [PDF of Chapter 1]