Evidence

Evidence and Epistemology

The concept of evidence is linked closely to epistemological notions of truth and of what constitutes knowledge. Inherently, there is a deeper philosophical or value-laden component when evidence is considered, and how and whether evidence is viewed as such is dependent on an underlying worldview, theory, or paradigm. Although it is important for qualitative researchers to be knowledgeable of method, they should be aware of and reflect critically on these underlying epistemological dimensions.

Evidence as the Basis for Qualitative Research

Evidence can justify and inform a qualitative study. The vast majority of qualitative researchers recognize that evidence regarding the world can be derived from formal knowledge sources such as previous research studies and theory. In many (but not all) instances, qualitative researchers should be aware of this formal knowledge prior to commencing a study and should use it where appropriate to inform their proposed research questions. Before drawing on this evidence to guide inquiry, researchers must also assess whether the research and theory are trustworthy or convincing and should ascertain whether and where important omissions are evident. Hence, comprehensive searching, appraisal, and meta-synthesis of existing literature are important steps in the beginning stages of the qualitative research process. Some approaches, particularly some forms of grounded theory and phenomenology, emphasize far less a reliance on drawing on or responding to previous evidence to guide qualitative inquiry. Evidence for the importance of these studies will rely on personal experience far more.

Evidence and the Process of Qualitative Research

Evidence is equally critical during the qualitative data collection, analysis, and presentation phases of research to ensure methodological rigor. Approaches to qualitative research generally purport that the perspectives and behaviors of humans are integral to understanding and explaining the social world. Appropriate sampling strengthens rigor. Qualitative research should seek to collect data in the right settings with appropriate participants; this is invariably dependent on the research question. However, a common principle of effective sampling is to generate data with strategically selected individuals and settings optimally well placed to generate insights (i.e., provide [Page 308]credible evidence) regarding the phenomena being explored. In instances where the participants and/or settings are very different from people and/or settings elsewhere, the transferability of findings is reduced and the wider applicability of the qualitative research is compromised.

The rigor of qualitative findings can also be affected by other dimensions of evidence and method during the research process. What is the evidence that data have been analyzed adequately? During analysis, seemingly outlying themes should specifically be sought and explored. What is the evidence that the researcher's interpretations are appropriate and reflect the data adequately? The trustworthiness of findings can be increased via recourse to evidentiary quotations from the data. Audit trails can also be collated to show how the researcher interpreted the qualitative data and addressed issues of reflexivity. In this way, notions of evidence are threaded throughout the process of qualitative research.

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