Diversity and Evidence in Minipublics. A select sample of citizens, a minipublic, advises a policymaker on the desirability of a policy by discovering citizen-specific evidence. A citizen's incentives to seek evidence hinge on the diversity of the minipublic and the political uncertainty regarding policy adoption. What is the policymaker's optimal choice of a minipublic when constrained by such endogenous evidence discovery? We show that political uncertainty is detrimental to evidence discovery within the minipublic; this is so even when evidence is costless and transparent, citizens are civic-minded, and the policymaker's interests are on average aligned with those of the citizens'. Relative to the most informative one, the optimal minipublic is distorted to be less diverse in order to sustain citizens' incentives. With a sufficiently heterogeneous citizenry, no evidence discovery through minipublics is possible at all.