Qualitative research seeks out the ‘why’, not the ‘how’ of its topic through the analysis of unstructured information – things like interview transcripts and recordings, emails, notes, feedback forms, photos and videos. (From QSR International.)
Qualitative data analysis (QDA) is the range of processes and procedures whereby we move from the qualitative data that have been collected into some form of explanation, understanding or interpretation of the people and situations we are investigating. (From Online QDA.)
Qualitative vs. quantitative research (from Xavier University Library).
In general, consider qualitative research when:
(Adapted from Price and Brown & Lloyd, Advances in Psychiatric Treatment (2001) 7:350-6.)