more environmental variables (biodiversity, water quality, carbon storage). Failing to exploit the differences in the costs of providing environmental services across farms leads to unnecessarily costly and ineffective schemes. The cost of policy simplification has been measured in a new study by researchers in the UK, US, Denmark and the European Commission's Joint Research Centre and published in Ecology Letters . Their point is that it is worth going for more individualised, complex schemes in spite of the much higher administrative costs implied by this approach. Indeed, they conclude that the additional implementation costs that accompany policies that account more fully for variation in the costs faced by landowners would be worth bearing even if they constituted more than 70% of the payments that would otherwise go to farmers. Methodology It is worth understanding the reasoning behind this claim. The authors investigate a sample of extensive livestock farms in the Peak District National Park in the UK. They first note the inefficiency of flat-rate payments, which in principle are designed to compensate farmers for income foregone in undertaking management prescriptions. They find that only between 12 and 46% of the payments are justified on this basis, although they also note that these are economically marginal farms and that without the AEM payment many of these farms would have a negative farm income and would be likely to go out of business. The difficulty for a government agency purchasing environmental services is that they do not know the individual cost to