How much inequality is too much, and how would you know?

Almost everyone accepts some differences in income and wealth, since people choose different work, take different risks and have different talents. Few accept any level at all. The hard question is where the line sits and what evidence should guide it.

Richard Wilkinson's talk "How economic inequality harms societies" argues that more unequal societies tend to do worse on a range of social outcomes. His argument has supporters and critics, and the debate is worth knowing about in both directions.

We are asking readers to propose a test. A good answer would say what outcome you would measure, such as health, trust, mobility or political voice; what level of inequality would worry you and why; whether you care about the gap itself or about people at the bottom; and what evidence would change your mind.

Concrete comparisons between countries or over time, using public data, are especially welcome.