Humans are fundamentally social. Social activities require coordination, which may yield multiple equilibria in the form of stable, self-reinforcing patterns of herd behavior. Since environmental impacts can differ substantially between alternative equilibria, such self-reinforcing behaviors...

1. Introduction -- 2. The purpose of a project analysis -- 3. Types of analysis -- 4. Efficiency -- 5. Utility -- 6. Social welfare -- 7. Equal welfare weights -- 8. Benefits measured in environmental units -- 9. Disagreement -- 10. Willingness to pay for the social good -- 11. The main message...