 The broad RCT approach endorses the formal preference model of the classical model; it only rejects the narrow interpretation of preferences as self-interested. Individuals may have non-self-interested preferences. They may have “pro-social” preferences that reflect a concern for others. They may have preferences for “fairness” which reflect a “preference” for more equal distributions of benefits and burdens. Indeed, one might posit preferences that reflect concerns for almost anything. The approach thus risks the ad hoc ascription of preferences, an issue discussed further in section 4. 