The Ultimate Guide to Using a Decision Journal

Success is the cumulative result of decision-making, yet most people fail to improve this skill because they judge processes based on outcomes—a fallacy known as "resulting." Implementing a decision journal, a practice advocated by Nobel laureate Daniel Kahneman, serves as quality control for thinking by documenting the situation, expectations, and reasoning before a choice is finalized. This method effectively combats hindsight bias, which distort’s one's memory of past logic to favor current results. By reviewing these entries every six months, individuals can distinguish between being "smart and unlucky" versus "stupid and lucky," revealing whether successes stem from sound judgment or mere chance. Effective journaling requires direct, simple language—clear enough for an eight-year-old to understand—to eliminate the "wiggle room" provided by jargon and vague terms. Ultimately, the goal is to align internal knowledge with reality by identifying recurring patterns in misaligned predictions.