Proponents of evidence-based policy (EBP) call for public policy to be informed by high-quality evidence from randomized controlled trials. This methodological preference aims to promote several epistemic values, e.g. rigour, unbiasedness, precision, and the ability to obtain causal conclusions. I argue that there is a trade-off between these epistemic values and several non-epistemic, moral and political values. This is because the evidence afforded by standard EBP methods is differentially useful for pursuing different moral and political values. I expand on how this challenges ideals of value-freedom and -neutrality in EBP, and offer suggestions for how EBP methodology might be revised.