Despite global recognition of the importance of human resources for health (HRH) in achieving health system goals, very little is known about what works, for whom and under what circumstances, especially for low-income and middle-income countries. Several important events and reports have called for increased funding and capacity for HRH research in recent years and several initiatives have started as a result. Progress has been slow, however. The following strategies can be most valuable in ensuring the relevance of the generated evidence for decision making and its contribution to stronger health systems. The first is to promote national processes to set priorities for HRH research with active participation from decision makers. The second is to make conscious efforts to scale up primary research to address priority questions and to develop sustainable mechanisms to evaluate the impact of current or new HRH strategies to feed into the policy making process. The third is to invest in the development of systematic reviews to synthesize available evidence and in the adaptation of the underlying methods to make them more responsive to the type of questions and the nature of research involving HRH issues. The fourth and most important is to consistently use a systems approach in framing and addressing research questions. While a narrow approach may be more attractive and simple, health systems and the problems facing them are not. Increasing the body of evidence that takes into account the complexity of health systems, and particularly human resources for health, will advance knowledge in this area and will make big strides in the quality and usefulness of the generated evidence.