Qualitative research uses its own distinct sets of research methods and sources of data in order to answer questions that would not otherwise be possible to answer.
Denzin and Lincoln provide a definition of qualitative research in the Sage Handbook of Qualitative Research (2011)
Qualitative research involves the studied use and collection of a variety of empirical materials—case study, personal experience, introspection, life story, interview, artifacts, and cultural texts and productions, along with observational, historical, interactional, and visual texts—that describe routine and problematic moments and meanings in individuals’ lives.
Coursera offers online learning opportunities in qualitative research. Courses are offered at scheduled times throughout the year. Examples include Qualitative Research Methods (University of Amsterdam), Qualitative Research (University of California, Davis), and Qualitative Comparative Analysis (Erasmus University, Rotterdam). Most Coursera courses are free.