Triangulation is a way of assuring the validity of research results through the use of a variety of research methods and approaches. It is a means of overcoming the weakness and bias, which can arise from the use of only one of the methods we have described, such as observation, questionnaires, etc. 

For example, researchers might choose to begin their research with an unstructured interview. This will allow them to identify key issues and appropriate terms which they can then use as a basis for more formal interviews, questionnaires, etc. 

Triangulation also allows researchers to collect both quantitative and qualitative data from both primary and secondary sources.


There are four types of triangulation:

  • Data triangulation involves time, space and persons. For example, research can be carried out at different time periods across different cultures, using a number of different people. 
  • Investigator triangulation uses multiple rather than single observers to record the same event. 
  • Theory triangulation employs a number of different theories to explain the conclusions of the research. 
  • Methodological triangulation is a combination of any of these methods.