The debate about the «right» designs for nursing research is on-going. According to international surveys, studies on the effectiveness and safety of nursing interventions are rare. Thus one could assume that nurses frequently expose patients in hospitals and nursing homes to unproven therapeutic and preventive nursing interventions. Nursing interventions are predominately of a complex nature, consisting of several components depending on and interacting with each other and their complex contextual factors. Thus, evaluation studies are often challenging and need careful development, ambitious designs and systematic evaluations. The UK Medical Research Council (MRC) has proposed a framework, where qualitative and quantitative research rely on and cross-fertilize each other in order to develop theory-based complex interventions, prepare and conduct their optimal delivery, explain how and why the interventions work and which conditions contributed in case they did not work. The present essay outlines the points where qualitative research contributes towards the development and evaluation of complex interventions. Firstly, the UK MRC framework is introduced, and secondly it is illustrated where qualitative research should be located by using examples from a handful of qualitative studies. Future clinically meaningful and implementable nursing interventions should best be developed by research groups with both excellent qualitative and quantitative research skills.

Keywords: Clinical nursing research, evaluation studies, qualitative research