Triangulation involves using multiple data sources in an investigation to produce understanding.

Some see triangulation as a method for corroborating findings and as a test for validity.  This, however, is controversial.  This assumes that a weakness in one method will be compensated for by another method, and that it is always possible to make sense between different accounts.  This is unlikely.  

Rather than seeing triangulation as a method for validation or verification, qualitative researchers generally use this technique to ensure that an account is rich, robust, comprehensive and well-developed.

Reasons to triangulate

A single method can never adequately shed light on a phenomenon.  Using multiple methods can help facilitate deeper understanding.

Denzin (1978) and Patton (1999) identify four types of triangulation:

  • Methods triangulation - checking out the consistency of findings generated by different data collection methods. 
    • It is common to have qualitative and quantitative data in a study
    • These elucidate complementary aspects of the same phenomenon
    • Often the points were these data diverge are of great interest to the qualiatitive researcher and provide the most insights
  • Triangulation of sources - examining the consistency of different data sources from within the same method.  For example:
    • at different points in time
    • in public vs. private settings
    • comparing people with different view points
  • Analyst Triangulation - using multiple analyst to review findings or using multiple observers and analysts
    • This can provide a check on selective perception and illuminate blind spots in an interpretive analysis
    • The goal is not to seek consensus, but to understand multiple ways of seeing the data
  • Theory/perspective triangulation - using multiple theoretical perspectives to examine and interpret the data


Angen, MJ. (2000). "Evaluating interpretive inquiry: Reviewing the validity debate and opening the dialogue." Qualitative Health Research. 10(3) pp. 378-395.

Creswell, JW. (1998). Qualitative Inquiry and Research Design Choosing Among Five Traditions. Thousand Oaks, CA: Sage Publications.

Denzin, NK. (1978). Sociological Methods. New York: McGraw-Hill.

Lincoln, YS. & Guba, EG. (1985). Naturalistic Inquiry. Newbury Park, CA: Sage Publications.

Mays, N. & Pope, C. (2000). "Qualtative research in health care:  Assessing quality in qualitative research." BMJ. 320(7226), 50-52.

Patton, MQ. (1999). "Enhancing the quality and credibility of qualitative analysis." HSR: Health Services Research. 34 (5) Part II. pp. 1189-1208.

Patton, MQ. (2001). Qualitative Evaluation and Research Methods (2nd Edition). Thousand oaks, CA: Sage Publications.