Triangulation in Qualitative Studies

The term so called triangulation might sould familiar by university students - especially by graduate students - who are interested in conducting qualitative studies. What is triangulation? What are the types of triangulation? and How to deal wit it? This post attempts to uncover these questions.

Technical Definition of Triangulation in Qualitative Study

In qualitative study, triangulation is described as a method which is intended to inform the validity of the qualitative study. Technically, it refers to multiple methods or data sources in qualitative research to develop a comprehensive understanding of phenomena1. Furthermore, it is qualitative research strategy to test validity through the convergence of information from different sources2.

Kinds of Triangulation in Qualitative Study

Literatue explains that validity informs whether the findings of qualitative study are true and certain. "True" in the sense of your findings accurately reflecting the real situation. "Certain" in the sense of your findings being backed by evidence. “Certain” means that there are no good grounds for doubting the results; i.e. the weight of evidence supports your conclusions 3 4.

Furthermore, it is revealed five types of triangulation, they are (1) data triangulation; (2) investor triangulation; (3) theory triangulation; (4) methodological triangulation; and (5) environmental triangulation 3 4 2 5.

No. Triangulation Description
1. Data Involves the use of different sources of data/information. A key strategy is to categorize each group or type of stakeholder for the evaluated program. The researcher should be certain to include a comparable number of people from each stakeholder group in the evaluation study.
2. Investor Involves using several different investigators/evaluators in an evaluation project. Typically, this would manifest as an evaluation team that consists of colleagues within the field of study. In order to triangulate, each different evaluator would study the program using the same qualitative method (interview, observation, case study, or focus groups). The findings from each evaluator would then be compared. If the findings from the different evaluators arrive at the similar - or closesly similar - conclusion, then validity has been established. If the conclusions differ substantially, then further study is warranted to uncover the true and certain finding.
3. Methodology Involves the use of multiple qualitative and/or quantitative methods to study the program. If the conclusions from each of the methods are similar (or closesly similar), then validity has been established.
4. Theory Involves the use of multiple professional perspectives to interpret a single set of data/information. Theoretical triangulation entails using professionals outside of field of study.
5. Environment Involves the use of different locations, settings and other key factors related to the environment in which the study took place, such as time of the day, day of the week or season of the year. The key is identifying which environmental factor, if any, may influence the information you received during the study. The environmental factor is changed to see if the findings are the same. If the findings remain the same under varying environmental conditions, then validity has been established.

In real world application, triangulation can be analogized as an effort to verify the credibility of information. In the case of qualitative study, it aims at ensuring that the data collected truly describe phenomenon being investigated thoroughly.


  1. Patton, M.Q. (1999). Enhancing the quality and credibility of qualitative analysis. Health Sciences Research, 34, 1189–1208. ↩︎

  2. Carter, N., Bryant-Lukosius, D., DiCenso, A., Blythe, J., & Neville, A. J. (2014). The Use of Triangulation in Qualitative Research. Oncology Nursing Forum, 41(5), 545–547. doi:10.1188/14.onf.545-547 ↩︎ ↩︎

  3. Guion, Lisa A. (2002). Triangulation: Establishing the Validity of Qualitative Studies. University of Florida. ↩︎ ↩︎

  4. Guion, Lisa A., David C. Diehl, and Debra McDonald. 2011. “Triangulation: Establishing the Validity of Qualitative Studies: FCS6014/FY394, Rev. 8/2011”. EDIS 2011 (8):3 ↩︎ ↩︎

  5. Sands, R. G., & Roer-Strier, D. (2006). Using Data Triangulation of Mother and Daughter Interviews to Enhance Research about Families. Qualitative Social Work: Research and Practice, 5(2), 237–260. doi:10.1177/1473325006064260 ↩︎

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