Daniel Kahneman, Olivier Sibony, and Cass Sunstein open by presenting 'noise' — unwanted variability in professional judgments that should ideally be consistent — as producing significant, often overlooked costs across numerous professional and organizational contexts.

Why this noise concept deserves significant new attention:

• Prior research and public attention have primarily focused on 'bias' — systematic errors in judgment — while the authors argue noise, unwanted inconsistent variability, represents an equally significant but historically underappreciated source of judgment error
• This distinction between bias and noise provides an important additional analytical dimension for understanding professional judgment quality across various significant decision-making contexts
• This opening establishes the book's foundational conceptual distinction, motivating its subsequent detailed examination of noise's significant costs and potential remedies

This opening establishes the book's foundational distinction between bias and noise, positioning unwanted judgment variability as an equally significant but historically underappreciated source of professional decision-making error.