What is Validity and Reliability in Qualitative research?
In Quantitative research, reliability refers to consistency of certain measurements, and validity – to whether these measurements “measure what they are supposed to measure”. Things are slightly different, however, in Qualitative research.
Reliability in qualitative studies is mostly a matter of “being thorough, careful and honest in carrying out the research” (Robson, 2002: 176). In qualitative interviews, this issue relates to a number of practical aspects of the process of interviewing, including the wording of interview questions, establishing rapport with the interviewees and considering ‘power relationship’ between the interviewer and the participant (e.g. Breakwell, 2000; Cohen et al., 2007; Silverman, 1993).
What seems more relevant when discussing qualitative studies is their validity, which very often is being addressed with regard to three common threats to validity in qualitative studies, namely researcher bias, reactivity and respondent bias (Lincoln and Guba, 1985).
Researcher bias refers to any kind of negative influence of the researcher’s knowledge, or assumptions, of the study, including the influence of his or her assumptions of the design, analysis or, even, sampling strategy. Reactivity, in turn, refers to a possible influence of the researcher himself/herself on the studied situation and people. Respondent bias refers to a situation where respondents do not provide honest responses for any reason, which may include them perceiving a given topic as a threat, or them being willing to ‘please’ the researcher with responses they believe are desirable.
Robson (2002) suggested a number of strategies aimed at addressing these threats to validity, being prolonged involvement, triangulation, peer debriefing, member checking, negative case analysis and keeping an audit trail.
So, what exactly are these strategies and how can you apply them in your research?
Prolonged involvement refers to the length of time of the researcher’s involvement in the study, including involvement with the environment and the studied participants. It may be granted, for example, by the duration of the study, or by the researcher belonging to the studied community (e.g. a student investigating other students’ experiences). Being a member of this community, or even being a friend to your participants (see my blog post on the ethics of researching friends), may be a great advantage and a factor that both increases the level of trust between you, the researcher, and the participants and the possible threats of reactivity and respondent bias. It may, however, pose a threat in the form of researcher bias that stems from your, and the participants’, possible assumptions of similarity and presuppositions about some shared experiences (thus, for example, they will not say something in the interview because they will assume that both of you know it anyway – this way, you may miss some valuable data for your study).
Triangulation may refer to triangulation of data through utilising different instruments of data collection, methodological triangulation through employing mixed methods approach and theory triangulation through comparing different theories and perspectives with your own developing “theory” or through drawing from a number of different fields of study.
Peer debriefing and support is really an element of your student experience at the university throughout the process of the study. Various opportunities to present and discuss your research at its different stages, either at internally organised events at your university (e.g. student presentations, workshops, etc.) or at external conferences (which I strongly suggest that you start attending) will provide you with valuable feedback, criticism and suggestions for improvement. These events are invaluable in helping you to asses the study from a more objective, and critical, perspective and to recognise and address its limitations. This input, thus, from other people helps to reduce the researcher bias.
Member checking, or testing the emerging findings with the research participants, in order to increase the validity of the findings, may take various forms in your study. It may involve, for example, regular contact with the participants throughout the period of the data collection and analysis and verifying certain interpretations and themes resulting from the analysis of the data (Curtin and Fossey, 2007). As a way of controlling the influence of your knowledge and assumptions on the emerging interpretations, if you are not clear about something a participant had said, or written, you may send him/her a request to verify either what he/she meant or the interpretation you made based on that. Secondly, it is common to have a follow-up, “validation interview” that is, in itself, a tool for validating your findings and verifying whether they could be applied to individual participants (Buchbinder, 2011), in order to determine outlying, or negative, cases and to re-evaluate your understanding of a given concept (see further below). Finally, member checking, in its most commonly adopted form, may be carried out by sending the interview transcripts to the participants and asking them to read them and provide any necessary comments or corrections (Carlson, 2010).
Negative case analysis is a process of analysing ‘cases’, or sets of data collected from a single participant, that do not match the patterns emerging from the rest of the data. Whenever an emerging explanation of a given phenomenon you are investigating does nto seem applicable to one, or a small number, of the participants, you should try to carry out a new line of analysis aimed at understanding the source of this discrepancy. Although you may be tempted to ignore these “cases” in fear of having to do extra work, it should become your habit to explore them in detail, as the strategy of negative case analysis, especially when combined with member checking, is a valuable way of reducing researcher bias.
Finally, the notion of keeping an audit trail refers to monitoring and keeping a record of all the research-related activities and data, including the raw interview and journal data, the audio-recordings, the researcher’s diary (see this post about recommended software for researcher’s diary) and the coding book.
If you adopt the above strategies skilfully, you are likely to minimize threats to validity of your study.
Don’t forget to look at the resources in the reference list, if you would like to read more on this topic!
Breakwell, G. M. (2000). Interviewing. In Breakwell, G.M., Hammond, S. & Fife-Shaw, C. (eds.) Research Methods in Psychology. 2nd Ed. London: Sage.
Buchbinder, E. (2011). Beyond Checking: Experiences of the Validation Interview. Qualitative Social Work, 10 (1), 106-122.
Carlson, J.A. (2010). Avoiding Traps in Member Checking. The Qualitative Report, 15 (5), 1102-1113.
Cohen, L., Manion, L., & Morrison, K. (2007). Research Methods in Education. 6th Ed. London: Routledge.
Curtin, M., & Fossey, E. (2007). Appraising the trustworthiness of qualitative studies:
Guidelines for occupational therapists. Australian Occupational Therapy Journal,
Lincoln, Y. S. & Guba, E. G. (1985). Naturalistic Inquiry. Newbury Park, CA: SAGE.
Robson, C. (2002). Real world research: a resource for social scientists and practitioner-researchers. Oxford, UK: Blackwell Publishers.
Silverman, D. (1993) Interpreting Qualitative Data. London: Sage.