People often rely on mental shortcuts, known as heuristics, to help them make judgments and decisions quickly and efficiently. While, generally, these heuristics lead to accurate judgments, in certain circumstances, heuristics can bias problem-solving and decision-making producing errors with serious consequences. What We Know About Heuristics and Biases introduces the literature on heuristics and provides an assessment tool designed to obviate these problems. Measuring six cognitive and social biases-confirmation bias, fundamental attribution error, the bias blind spot, anchoring bias, representativeness bias, and projection bias-this tool provides an innovate and cutting edge method for assessment professionals and researchers in measurement.