The ultimate aim of a health care system is progression of community health in an equal manner and various factors can be contributed in achieving it. Many health policy makers or managers try to produce evidences to be used in the health care system for this goal and they need many types of scientific documents to make well-informed decisions [1].

For this reason, the importance of evidence-based health policy making as a complicated task that affects many various individual and organizational actions is completely determined. Evidence to inform managers or policy-makers can be found depending on several factors, such as: The timeframe in which a policy-maker requires a response, the available resources and global or local evidence required. The nature of policy-maker's request determines the type of evidence and its availability. If evidence is not found, the other measures available may require attention [2].

Many different databases, initiatives and search strategies are available internationally to support policy-makers. Based on the advice of the European Advisory Committee on Health Research in 2003, WHO/Europe has adopted an initial definition of evidence that included context-related information and research findings from other types of knowledge that may serve as a basis for decision-making in health care public health to better meet the needs of clients. Such research findings allow managers and policymakers to find the best available evidence based research to inform, make, or advocate for a decision about health care systems [3].

Developing evidence based health policy making requires addressing three phases. First of all, health care systems policymakers and researchers should be able to find best methods of classified topics which can include both health implementation strategies and system arrangements [4]. Second, policymakers and researchers should know when they can carry out comprehensive inventories that can answer the questions about cost-effectiveness and the effectiveness of policy options through single studies or systematic reviews about economic evaluations; and impact evaluations or both of them [5]. Third, they should be able to identify decision-relevant information by quickly assessment of the research results to know whether the reviews have high quality, whether the searches were conducted newly, and whether the studies were conducted in their health care system needs to impact on the applicability of the results [6].

In conclusion, an important challenge for researchers and policy-makers is to determine whether evidence about the effects of a policy is applicable to their settings. Therefore, they can easily access to many types of evidence based researches to inform advocacy and decision-making about their health care systems. They can also access complementary contents such as WHO policy-relevant documents to use best health policy as a roadmap for filling the research and strengthening the validity of technical decision-making gap.