Single Metric Obsession (Personal Goodhart's Law)

When a person reduces their life's success to a single measure—net worth, body weight, follower count, GPA, publication count—and optimizes ruthlessly for it at the expense of everything unmeasured. The pattern mirrors organizational Goodhart's Law but is more insidious because the person is both the metric-setter and the metric-subject, making the distortion invisible. The mechanism: (1) a meaningful metric is identified, (2) it becomes the primary feedback signal, (3) dimensions of life that don't feed the metric atrophy (relationships, health, creativity, joy), (4) the metric improves while overall wellbeing declines, (5) the person can't understand why they're unhappy because their 'number' is great. The Silicon Valley founder who optimizes for company valuation while their marriage collapses. The academic who optimizes for h-index while losing passion for their subject. The fitness obsessive who optimizes for body composition while becoming socially isolated. Each achieves their metric and feels empty.

When to use it

When your primary life metric is improving but you feel worse overall. When you notice entire life domains being neglected in service of one measure. When someone asks 'how are you?' and you answer with a number. During life review or goal-setting periods.

How it can help

Helps people recognize when they've collapsed a multi-dimensional life into a single number. The diagnostic: what metric do you check most often? What are you sacrificing for it without consciously choosing to? Prevention requires a 'life dashboard' with at minimum 5 metrics across different domains (health, relationships, financial security, meaningful work, growth/learning) where no single metric can dominate. Review the dashboard quarterly. The rule: any metric that's improving while two or more others are declining indicates single-metric obsession. The deeper fix: build identity around the portfolio, not any single metric.