Inconsistency in real-world judgments can cause random unfairness, injustice and misallocation of resources. In their recent monograph Kahneman, Sibony, and Sunstein (2021) analyse judgment inconsistency or "Noise," examine its sources and propose remedies. In this commentary on Kahneman et al., we reflect on the major concepts (such as "judgment," "noise," "error," and "bias") used in analysing inconsistency. We place this work in the broader context of applied cognitive psychology, relating it to error typologies and to dual-systems views of thinking. We also compare Kahneman et al.'s heuristics based approach to the linear combination of attributes based approach of Social Judgment Theory (SJT), with particular reference to judgment noise. We conclude that the main contributions of Kahneman et al.'s book are: (1) to raise awareness of the pervasiveness of judgment noise across a range of important real-world areas; (2) to provide a taxonomy of types of noise in terms of system noise versus occasion noise, and level noise versus pattern noise; and (3) to outline useful ways of reducing noise, and thus overall levels of error.