Which of the following is a scientific criterion appropriate for qualitative research?

Auditability is a key scientific criterion in qualitative research that emphasizes the transparency and traceability of the research process. This involves maintaining a clear and documented account of how data was collected, analyzed, and interpreted, which allows others to follow the researcher's steps and verify the findings. In qualitative research, where subjective experiences and interpretations are often examined, auditability ensures that the research is conducted rigorously and that the conclusions drawn are credible and trustworthy.

In comparison, reliability typically pertains to quantitative research and focuses on the consistency of a measure. The scale of measurement relates to how variables are quantified and is more relevant in quantitative studies. Magnitude usually refers to the strength or size of an effect or difference, which is also not a primary concern in qualitative research where the focus is on understanding meanings and experiences rather than quantifying them. Therefore, auditability is the most appropriate criterion for ensuring the quality and credibility of qualitative investigations.