How to Triangulate Data Sources


In this episode, I discuss triangulation when doing qualitative research. Newsletter: How to Triangulate Data Sources – Benjamin L. Stewart ( 

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Adding Validity to Qualitative Studies

For those who are taking Thesis Seminar, the topic today relates to triangulating your data sources. Triangulation applies to qualitative and mixed-method studies and involves collecting two or more types of data to better understand what you are researching.

Some examples of different data sources that might apply to your study include the following:

  1. classroom observations (board work, teacher behaviors, student behaviors, classroom discourse, etc.) – required by all students.
  2. teacher interviews
  3. stimulated recall
  4. student interviews
  5. teacher focus groups
  6. student focus groups
  7. administrator interviews
  8. administrator focus groups
  9. teacher questionnaires
  10. student questionnaires
  11. administrator questionnaires
  12. parent interviews
  13. parent questionnaires
  14. parent focus groups
  15. student work (i.e., assignments, homework, projects, handouts, etc.)
  16. document or content analysis (i.e., school policies, curriculum, syllabus, lesson plan, handbooks, manuals, etc.)

From the above list, some data sources will be more appropriate than others. Your job as the researcher is to determine which combination of three data sources will best answer your research questions.

What order should I follow to collect my data?

The order in which you collect your data will depend on your research questions and the participants you have chosen for your study. Ideally, you will want to avoid influencing the participants as much as possible. If you have chosen your participants purposefully, you should have some idea that their current teaching practice is likely to provide you the data you’ll need to answer your research questions. If this turns out to be the case, then you will want to choose the data sources and the appropriate order to collect your data so as not to influence or reveal too much about your study to the teachers, students, administrators, etc. Realize that as you get into your study and you begin applying questionnaires, interviews, etc. that naturally the participants may become more knowledgeable about your study. Again, the idea is to attempt to not influence them more than you possibly can.

There might be some cases where teachers are likely to not provide you the data you need to answer your research questions. In this case, you’ll need to consider doing an intervention. An intervention is when you intervene in the study by working with the participants in a way that offers suggestions or solutions so they are more likely to provide the data you need to answer your research questions. For example, when working with a teacher, you might suggest a teaching technique, technology, etc. that will help achieve your research objective. The trick is to intervene as little as possible or gradually increase the intervention until they can perform as you intended. Once you have chosen to do an intervention, realize that what you discuss with the participants (e.g., teachers) is also a data source. What you suggest to the teachers and how they reply is a key part of the study which would later then be compared to your classroom observations, subsequent interviews, etc.

Regardless of whether you do an intervention or not, triangulate your data sources when doing a qualitative study. Avoid presenting any data unless you have at least one (preferably two) other data sources to compare it to.

Published by Benjamin L. Stewart


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