Qualitative research seeks to understand how people make sense of their experiences in the world (Merriam, 2009) by exploring non-numerical data (Nkwi, Nyamongo & Ryan, 2001).
According to FHI et al., the most important characteristic distinguishing qualitative research from quantitative research is the flexibility of qualitative research methods. For example, open-ended questions in surveys allow for greater variety of responses, which can evoke responses with the following qualities:
Further, qualitative approaches may allow a "researcher the flexibility to probe initial participant responses...to encourage them to elaborate...."
Family Health International, Mack, N., Woodsong, C., & United States Agency for International Development. (2005). Qualitative research methods: A data collector's field guide. North Carolina: FLI. Retrieved from https://youthsextion.files.wordpress.com/2011/04/06fhiqualitative-rm.pdf.
Kellam, L., & Thompson, K. (Eds.). (2016). Databrarianship : The academic data librarian in theory and practice. Retrieved from https://ebookcentral-proquest-com.proxy.library.nd.edu
Merriam, Sharan B. (2009) Qualitative research :a guide to design and implementation San Francisco, Calif. : Jossey-Bass.
Nkwi P, Nyamongo I, Ryan G. Field Research into Social Issues: Methodological Guidelines. Washington, DC: UNESCO, 2001.
Visit Duke University Library's qualitative research guide for an excellent table summarizing the major characteristics of a variety of qualitative methods.