Accountability pressures are a ubiquitous feature of social systems: virtually everyone must answer to someone for something. Behavioral research has, however, warned that accountability, specifically a focus on being responsible for outcomes, tends to produce suboptimal judgments. We qualify this view by demonstrating the long-term adaptive benefits of outcome accountability in uncertain, dynamic environments. More than a thousand randomly assigned forecasters participated in a ten-month forecasting tournament in conditions of control, process, outcome or hybrid accountability. Accountable forecasters outperformed non-accountable ones. Holding forecasters accountable to outcomes (“getting it right”) boosted forecasting accuracy beyond holding them accountable for process (“thinking the right way”). The performance gap grew over time. Process accountability promoted more effective knowledge sharing, improving accuracy among observers. Hybrid (process plus outcome) accountability boosted accuracy relative to process, and improved knowledge sharing relative to outcome accountability. Overall, outcome and process accountability appear to make complementary contributions to performance when forecasters confront moderately noisy, dynamic environments where signal extraction requires both knowledge pooling and individual judgments.