A strategy to improve expert technology forecasts

Forecasts of the future cost and performance of technologies are often used to support decision-making. However, retrospective reviews find that many forecasts made by experts are not very accurate and are often seriously overconfident, with realized values too frequently falling outside of forecasted ranges. Here, we outline a hybrid approach to expert elicitation that we believe might improve forecasts of future technologies. The proposed approach iteratively combines the judgments of technical domain experts with those of experts who are knowledgeable about broader issues of technology adoption and public policy. We motivate the approach with results from a pilot study designed to help forecasters think systematically about factors beyond the technology itself that may shape its future, such as policy, economic, and social factors. Forecasters who received briefings on these topics provided wider forecast intervals than those receiving no assistance. Forecasts of the future cost and performance of technologies are used in planning a sustainable energy future, as well as to support decision-making in many other public and private contexts (1-6). These forecasts are intended to help decision-makers anticipate future events, avoid surprises, and allocate resources effectively. To that end, technology forecasts should be both as accurate as possible and properly qualified, so that decision-makers know how heavily to