A heuristic is a mental shortcut or rule of thumb you use to make judgments. Heuristics can help you to make judgments quickly and efficiently. Your textbook describes several heuristics, including the availability heuristic and the representativeness heuristic. These heuristics depend on information that is stored in your memory. Sometimes the information in your memory is not accurate. When you use a heuristic based on inaccurate information, you may make a misjudgment. If you misjudge something, you risk making a poor decision.