Triangulation with Data Sources in Qualitative Research
Julie Zahle
20 November 2025
In a qualitative study, a research participant tells the researcher that when the police searched him, they took his money, and that the police standardly run the names of visitors and patients at hospitals. The qualitative researcher is unsure whether to trust these reports: are the claims really true?
In situations like this, qualitative researchers often use confirmatory data source triangulation. Accordingly, they seek to increase the confirmation of an initial report through collecting convergent reports from additional data sources. As it stands, this account of the strategy is too crude. Surprisingly, however, a more detailed explication of data source triangulation has not been offered within the social science literature. And within the philosophy of science literature, the strategy is barely mentioned and not adequately covered by accounts of other forms of triangulation.
In the first part of this talk, I provide a thorough account of data source triangulation for the purposes of confirmation in qualitative research. Next, I illustrate, and expand on, the account through an examination of a recent debate on the topic sparked by Alice Goffman’s ethnographic (qualitative) study “On the Run. Fugitive Life in an American City” (2014). Steven Lubet was a key figure in the debate, and I consider his criticisms of the use of data source triangulation in Goffman’s book and ethnography more generally. Lastly, I consider possible objections to my account of confirmational data source triangulation.
