Qualitative Analysis in Case Study

Multiple Triangulation

By combining methods in the same study a researcher can partially overcome or counterbalance the deficiencies and biases that flow from single methodologies. Robert Yin claims that the most important advantage presented by using multiple sources of evidence is the development of converging lines of inquiry. Any conclusion in a case study is likely to be more convincing if it is based on several different sources of information.

Norman Denzin, in his 1989 book, distinguishes four types of triangulation, an approach he termed multiple triangulation: (1) data triangulation, (2) investigator triangulation, (3) theory triangulation, and (4) method triangulation. Judith Kimchi, Barbara Polivka, and Joanne S. Stephenson add a fifth type: analysis triangulation, and Matthew Miles and Michael Huberman made a further distinction between data source triangulation and data type triangulation. The following list provides more detail on all types of triangulation.

• Data source triangulation: Data are gathered through several sampling strategies, at different moments in time, in different social situations (space), and with a variety of persons.
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• Investigator triangulation: More than one researcher is involved in a research project.
• Theory triangulation: More than one theoretical position is used to collect and interpret data.
• Methodological triangulation: More than one method is used to gather data (e.g., interviewing, participant observation filming).
• Data type triangulation: Several types of data are used to understand the case or cases at hand. These can include interview transcripts, visual data, and official statistics and are a result of the triangulation of methods.
• Analysis triangulation: Several separate analytic techniques are used to validate meaning in the data set. Analysis triangulation can also involve multiple units and levels of analysis (e.g., individuals, families, settings). The combination of analytic techniques enhances the breadth and depth of what researchers see in their data.

Multiple triangulation is a way to confirm the breadth and accuracy of the data set and its interpretation. It may be conceptualized as a means of achieving convergent validity, as Yin did. However, confirmation is not always, or necessarily, the outcome of triangulation. When one is studying complex social phenomena, multiple strategies combined may address unique angles or contribute different viewpoints. Therefore, triangulation cannot increase validity in the sense of pursuing objective truth; instead, it adds to the investigator's depth and breadth of understanding of a phenomenon, as Denzin shows in citing data from Fielding and Fielding's 1986 publication. Triangulation is thus seen as a means of enhancing the completeness of the findings, rendering a more in depth understanding.

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