The evidence- based policy is defines as an approach that supports the decision making process through providing the best evidence possible which in turn allows to undertake well- informed decisions. Decades ago, concerns about the quality of the evaluations were in the center of the debate. However, currently such concern has switched to the use of evaluations in the policy making process (http://www.unicef.org/ceecis/evidence_based_policy_making.pdf). In other words, the use of the findings of evaluations is still low in despite of the substantial resources employed and the recognized importance that evaluations hold. Therefore, the question is: Is the evidence generated useful for policymakers? According to Weiss (http://evi.sagepub.com/content/5/4/468.abstract), there are four factors that influence on the use of the results of evaluations: interests, ideologies, institutional culture, and information sources. If there is a conflict between any of these factors and the evidence provided, there is less likelihood that it can be used in the policy making process. Therefore, the criteria for policymakers in using evidence goes beyond the technical judgement, as the use of the information presented as part of the evidence should harmonize in the best way possible with the different interests and institutions involved in the policy making process.
Other factors which may influence in the use of evidence in the policy making process is the timely provision of results, the capacities of institutions, and unanticipated contingencies that may arise. For example, most of the time policymakers need the information as soon as possible and cannot wait until the termination of evaluations. However, these reasons should not being seen as obstacles, as the evidence-based policy is a process which considers operational aspects such the mentioned above. Also, towards contingencies, the evidence-based policy process provides useful information that allows a better characterization of the problem.
Another author, Innvaer (http://hsr.sagepub.com.ezproxy.is.ed.ac.uk/content/7/4/239.full.pdf+html), posits the “two community thesis”, which states that there is a “divorce” between the scientific community and policymakers due to conceptions that one group has towards the other one. Scientists usually perceive themselves as “rational, objective and innovative” and perceive policymakers and politicians as “interested-driven actors immune to innovation and scientific evidence”. By contrast, policymakers and politicians perceive themselves as “responsible, action oriented and pragmatic leaders” and perceive scientists as “naïve and commonly disconnected with the actual reality”. Towards this scenario, Velasquez (https://www.researchgate.net/publication/260227233_EVIDENCE-_BASED_PUBLIC_POLICIES_THE_EXPERIENCE_OF_THE_MINISTRY_OF_DEVELOPMENT_AND_SOCIAL_INCLUSION) suggests the creation of a team of professionals within institutions, which can acts as a bridge between evaluators and policymakers. This team, known as “evidence managers”, are experts on political, technical, economic, and social analysis, who would use the recommendations as consequence of evaluations and would analyze the feasibility of the implementation of such recommendations. Then, they would include any adjustment and finally would be responsible for the follow-up of the implementation of recommendations.