Triangulation

Triangulation in qualitative research has come to mean a multimethod approach to data collection and data analysis. The basic idea underpinning the concept of triangulation is that the phenomena under study can be understood best when approached with a variety or a combination of research methods. Triangulation is most commonly used in data collection and analysis techniques, but it also applies to sources of data. It can also be a rationale for multiple investigators in team research. Questions that commonly arise in discussions of triangulation tend to address one of two concerns: the issues of using triangulation as a test of validity of research findings and the practical difficulties of using more than one method to study the same phenomenon.

The concept of triangulation is borrowed from navigational and land surveying techniques that determine a single point in space with the convergence of measurements taken from two other distinct points. The multimethod approach is seen to be a research strategy that can reduce biases or deficiencies caused by using only method of inquiry. Initially, in the 1950s and 1960s, triangulation was put forward as a way to increase the measures of validity or to strengthen the credibility of research findings by comparing the results of different approaches to a single unit of study. In other words, triangulation could measure what was thought to be the same thing by using different methods of investigation. However, the use of triangulation of methods to minimize measurement biases has been critiqued over the years by qualitative researchers for corresponding too closely to positivistic notions of reliability and validity. It is claimed that different approaches can measure different aspects of a research problem, but they also yield different kinds of data.

In qualitative inquiry, researchers tend to use triangulation as a strategy that allows them to identify, explore, and understand different dimensions of the units of study, thereby strengthening their findings and enriching their interpretations. However, there are differences among researchers and commentators on the nature, degree, and utility of comparison of findings garnered from different approaches.

Norman K. Denzin's widely cited work on the theoretical underpinnings and implications of combined methods in sociological qualitative research has popularized the definition of triangulation as a combination of methods used to study the interrelated phenomena from multiple and different angles or perspectives. His formulation of triangulation is still widely used by qualitative researchers and is comprised of four basic [Page 893]types: triangulation of methods of data collection, investigator triangulation, theory triangulation (including methodological variations that account for between-method and within-method approaches), and triangulation of data sources.