Balancing rigor and relevance is one of the tensions inherent in social work research...the two are not mutually exclusive. It is important in a dissertation to carry out rigorous systematic research underpinned by an appropriate epistemology or theory. This does not mean that your dissertation cannot address a practical problem. It does mean that you have to have to have a theoretical framework to explain your theory of change.
All questions have behind them theoretical foundations without the exploration of which the questions are impossible to answer...the purpose of research as theory building and testing.
The Dissertation: From Beginning to End
Peter Lyons & Howard J. Douek