Halo Effect

Overview

A single positive or negative impression biases judgments of all unrelated attributes. A "great" CEO is assumed to have great strategy, vision, and execution; a beloved brand's features are rated higher than equivalent features from less-loved brands. Documented by Thorndike (1920), formalized by Nisbett & Wilson (1977), applied to business analysis by Rosenzweig (2007) — who showed business books overclaim because their descriptions follow company performance, not underlying reality.

Composes with fundamental-attribution-error, narrative-fallacy, confirmation-bias, hindsight-bias, survivorship-bias.

When to Use

• Reading business books, case studies, or analyst reports
• Conducting or designing performance reviews
• Conducting or designing hiring interviews
• Evaluating vendor, supplier, or partner performance
• Evaluating investment opportunities or CEO impact
• Conducting self-assessment
• Someone says "halo effect," "visionary leader," "everything they do is great"
• An "AI company" label, a marquee investor, or a famous-lab pedigree is doing the rating's work — evaluating an AI vendor, an AI-boom valuation, or a fluent model answer rated as accurate because it sounds confident