The use of two or more independent sources of data or data collection methods within one study in order to help ensure that the data are telling you what you think they are telling you (Saunders, 2007).
Theory triangulation is part of the triangulation approach in mixed method research. The basic idea of the triangulation approach is to mix different types of data and theory analysis so that the researcher can build a “more valid and holistic picture of society than that which could be acquired by remaining true to only one set of methods” (Henn, Weinstein and Foard 2006:19).. In terms of theory, triangulation enables the researcher to mix theoretical approaches in interpreting data and analyzing the phenomena under study (Uyangoda, 2010).
References
Saunders, M.N., 2007. Research methods for business students, 5/e. Pearson Education India.
Uyangoda, J., 2010. Writing Research Proposals in the Social Sciences and Humanities: A theoretical and practical guide. Social Scientists’ Association.