An example she gives is a quota on sugar imports in the United States, which generates 2261 jobs at the expense of a general welfare reduction of $1,162 million (Hufbauer and Elliott, 1994). Then the implicit price for a job in the sugar industry is above $500,000, allowing for significant room for Pareto improvement. Political puzzles are cases where minority trumps majority. An example she gives is the rural bias in urbanized countries, such as the Common Agricultural Policy in the European Union. Lohmann claims that Olson's free-rider problem is insufficient to explain these puzzles. Instead, she argues they are due to uncertainty (information asymmetry among actors) when special interest groups evaluate how political actors promote their interests. She states that everyone can be considered a special interest. Because everyone is (relatively) sure how well their interests are represented, they give more weight to their interest representation when evaluating political actors than to the general benefit. Lohmann argues that it could be politically viable to focus on separate narrow interests at the expense of general benefits. Legitimacy Trumbull rejects the observation by Olson and Lohmann that concentrated interests dominate public policy. He points out that historically, diffuse interests nearly always found ways to be represented in public policy, such as the interests of retirees, patients or consumers. Trumbull explains this with the role of legitimacy of interest groups that promote policies. He argues that diffuse interests have a legitimacy premium when they manage to mobilize, while concentrated interests are viewed with suspicion. He describes the concept of legitimacy coalitions, which are coalitions between state policymakers, social activists or industry to promote certain policy. By having to form a coalition, the interests are more broadly represented. An example of such a coalition is the post-war neo-corporatist system. Critical mass Marwell and Oliver use mathematical and computational models to show that a number of the assumptions made by Olson are unrealistic, and if they are relaxed, the behavior of a system of rational agents changes dramatically. One assumption is that the "production function" of goods is linear. If this function instead accelerates, then a critical mass of early contributors can encourage a large number of others to contribute. Another assumption is that the cost of the good is a function of the size of the group that would benefit from it. For many public goods, this is not true, and Marwell and