Why Research (Does Not) Affect Policy?: Experimental Evidence on the Role of Political Bias

One of the critical issues in bridging the divide between scientific evidence and policy is the "perceived credibility" of the evidence. Policymakers may be more or less inclined to follow scientific evidence if they believe the messenger, i.e. who presents the scientific evidence, has an ideological agenda. This may be true even in policy areas with a pressing need for scientific evidence and even when the evidence is produced with the highest scientific standards. This study tests whether the divergence in political biases between who send the evidence and the politician who receives it affects policy adoption using a Randomized Controlled Trial (RCT). Exploiting a sample of all touristic municipalities in Spain, we send policymakers in these municipalities either a policy brief or a link to a newspaper article describing a high-quality scientific-evidence on a very low-cost and effective and uncontroversial policy to increase tourism. Furthermore, we create random variation in the identity of the source of the information to signal a possible ideological bias. We combine survey and administrative data to define our sample of treated and control municipalities and the random assignment to the different treatment arms. Ex post, we then compare different measures of interest in the scientific evidence and the recommended policy. Specifically, we investigate whether policy makers pay attention and read the recommended policy/ evidence and whether they eventually adopt the recommended policy.