Bias in experimental nursing research: Strategies to improve the quality and explanatory power of nursing science.

In a guest editorial in this journal, Rahm Hallberg [Rahm Hallberg, I., 2006. Challenges for future nursing research: providing evidence for health-care practice. International Journal of Nursing Studies 43, 923-927] called for research which has greater explanatory power to determine the effectiveness of nursing interventions. In this paper we critique the suggestion made by the evidence-based nursing movement that randomisation per se is the principal route to better quality nursing research. In contrast, we evaluate the new CONSORT criteria for pragmatic RCTs, which assess the quality of strategies to reduce selection, performance, attrition and detection biases, allowing many different types of comparative studies to be covered by application of the checklist. We propose that randomisation alone is a necessary but insufficient strategy and that nursing researchers rise to Rahm Hallberg's challenge by adopting the extended criteria to assist in the critical appraisal, design and reporting of all experimental research in nursing.