Revealed Preference¶

Why It Matters¶

People often say one thing and do another. They claim to value savings but don't save. They claim to want exercise but don't exercise. Revealed preference cuts through stated preference to what people actually want - as demonstrated by what they sacrifice to get.

The Key Move¶

When someone claims a preference, check behavior. What do they actually choose when facing trade-offs? What do they sacrifice to get what they supposedly want? If behavior contradicts statements, trust behavior.

Classic Application¶

Consumer behavior. Market research asking "would you buy X?" overestimates actual purchase behavior. What people say they'll buy isn't what they actually buy. Revealed preference (actual purchases) beats stated preference (survey responses).

Surprising Application¶

Self-knowledge. You may not know your own preferences. If you say you value family time but consistently work late, your revealed preference is for work (or money, or status). This isn't hypocrisy - it's information. Your behavior tells you about your actual values.

Failure Modes¶

• Ignoring constraints - behavior reveals constrained preferences, not unconstrained preferences
• Missing that revealed preferences can reflect mistakes, addiction, or weakness of will
• Treating all behavior as preference-revealing - some behavior is habitual or pressured
• Ignoring that preferences are constructed by choice situations, not just revealed
• Using revealed preference to dismiss stated preferences entirely - both contain information

Go Deeper¶

Samuelson's revealed preference theory. Sen's critiques and expansions.