Triangulation is a term in qualitative research methods derived from navigation, in which sailors try to discover their exact position on a map by taking bearings on two landmarks. The methodological triangulation is the most frequently applied approach, using different methods when studying a subject (1) such as the combination of ethnographic observations with interviews or the mixed methods approach which is mixing qualitative and quantitative methods in one study.(2) Denzin discerned three other types of triangulation next to the methodological triangulation: data, investigator and theory triangulation.(3) Data triangulation means that diverse sources of data are used studying a phenomenon in different settings; it results in a richer description of the phenomenon.(1) In investigator triangulation multiple observers in the same research field continually discuss their observations and interpretations through this de-biasing their personal preferences. Theory triangulation means that researchers approach their data with several hypotheses exploring how the data fit in each hypothesis.

1.  Seale C. Converging on a Point?  The Quality of Qualitative Research. London: SAGE Publications; 1999. p. 52-72.

2.  Stolper CF, Van de Wiel MWJ, Hendriks RHM, Van Royen P, Van Bokhoven MA, Van der Weijden T, et al. How do gut feelings feature in tutorial dialogues on diagnostic reasoning in GP traineeship? submitted. 2013.

3.  Denzin NK. The Research Act: a Theoretical Introduction to Sociological Methods. 3rd ed. New York: Prentince Hall; 1989 1989.