Improving Deliberative Environmental Management Under Uncertainty examined similarities and differences between expert and public understanding of uncertainty. This collection directly compares expert and layperson interpretations and understandings of different expressions of uncertainty, in the context of evaluating the consequences of proposed environmental management actions that influence economic, social, or health concerns. Data were collected via a Web-based survey where respondents were asked a series of questions after they were given four hypothetical scenarios on the following topics: wind farms, vegetation management, superfund site, and salmon. Each scenario described an environmental proposal along with pros and cons then respondents selected a response option with costs and benefits of the proposal in mind. The first scenario focused on a plan to manage forest vegetation in the northeastern United States, using either conventional methods involving aerial spraying of herbicides or more expensive hand spraying methods intended to reduce adverse impacts on local moose populations. The second scenario focused on a proposal to build a new windfarm in a western state, which would lower electricity rates to local communities but could have negative effects on resident songbird populations. The third scenario focused on a plan to clean up hazardous waste at a large industrial Superfund site. The waste was estimated to have caused 200 children to develop serious respiratory illness from exposure to contaminated drinking water; building a decontamination facility would reduce the number of sick children but would be very expensive and would take time to build. The fourth scenario focused on a plan to reduce the declining population of Chinook Salmon. In order to reduce the Chinook Salmon declines in the Seshon River, an advisory committee must find a balance between the protection of salmon and the use of water to generate electricity, which is a cause in salmon reduction. Participants responded to hypothetical but realistic scenarios involving trade-offs between options presented and other objectives, and were asked a series of questions about their comprehension of the uncertainty information, their preferred choice among the alternatives, and the associated difficulty and amount of effort. Respondents were asked general questions which ranged from how they felt about a particular issue to how easy or difficult it was to answer the questions associated with each scenario. Demographic information includes gender, age and education level.