Many decisions made by authorities pose uncertain consequences for the individuals affected by them, yet people must still look to the future and determine the extent to which they will support the change. Integrating the social justice and behavioral decision theory literatures, this article asserts that individuals determine their support for proposed initiatives by assessing how knowledgeable they feel and weighing two main sources of information more or less heavily: their prediction of how the consequences of the initiative are likely to affect them, or the perceived fairness of the decision making process. Three studies (two experiments, one field survey) assessing support for proposed public policies reveal that individuals who feel very knowledgeable rely more on their prediction of how the outcome will affect them, whereas those who feel less knowledgeable rely more on an overall impression of procedural fairness. The findings shed insights into how people use process and outcome information in reacting to decisions under uncertainty.