Mixed method research: Fundamental issues of design, validity, and reliability in construction research

The fact that people play key roles in nearly all aspects of construction suggests that effective construction research requires proper application of social science research methods. This is particularly true for researchers studying topics that involve human actions or behavior in construction processes, such as leadership, innovation, and planning. In social science research, no single method of data collection (survey, experiment, participant observation, or unobtrusive research) is ideal. Each method has inherent strengths and weaknesses. Careful attention to the methodological ABCs of the design process, as discussed here, can enhance the validity and reliability of a given study. Combining quantitative and qualitative approaches in research design and data collection, however, should be considered whenever possible. Such mixed-methods research is more expensive than a single method approach, in terms of time, money, and energy, but improves the validity and reliability of the resulting data and strengthens causal inferences by providing the opportunity to observe data convergence or divergence in hypothesis testing.