In addition to the three types of policies outlined earlier, a large group of supporting policies can improve the effectiveness and lower the cost of performance standards, research and development, and economic signals. Supporting policies tend to lower transaction costs, improve information, and streamline decision making.
For example, appliance efficiency labels are a type of supporting policy that doesn’t set minimum performance criteria or price in externalities but provides purchasers with better information that can push them to choose the most efficient goods.
There are many different supporting policies, some of which are included in the policy-specific sections of this website and book. However, these policies tend to be supportive of and secondary to the three types of policies discussed earlier.