Building on insights from cognitive psychology and scholarship on decision-making, this article examines the respective role of values and information, and the interaction between them, in the formation of expert judgment. We analyze data from an original expert survey on soil decontamination practices and test several hypotheses found in the literature. While it is common to assume that experts rely primarily on factual information when making decisions, we find that values may also orient the judgment of experts when such information is lacking. In such cases, experts may be influenced by their value predispositions, leading to a wider range of expert assessments. Conversely, the judgment of experts who possess the relevant information tends to converge on the best known outcomes. We thus find that relevant knowledge mediates the role of values in expert judgment. While suggesting that some caution should always be taken when deferring to experts, our findings suggest that governments and the public are justified in taking experts’ judgment seriously.