Paradigms, Purpose, and the Role of the Literature: Formulating a Rationale for Qualitative Investigations Haverkamp, B. E., & Young, R. A. (2007). Paradigms, purpose, and the role of the literature: Formulating a rationale for qualitative investigations. The Counseling Psychologist, 35(2), 265–294.
This article provides helpful information for developing a research purpose.