Evaluating the effectiveness of agricultural and rural policies: an introduction
介绍政策评估作为社会科学子学科的发展，聚焦农业与农村政策，特别是欧盟共同农业政策（CAP）的评估需求、方法工具及多目标复杂性，适合政策研究者与评估从业者快速了解该领域现状。
Over the last two decades, policy evaluation has emerged as a sub-discipline in its own right within social sciences. Also the attention of political institutions has sharply increased in this respect, particularly as regards agricultural and rural policies, since they are persuaded that any future development in policy making should be necessarily grounded on a rigorous and systematic evaluation work. In the case of the Common Agricultural Policy (CAP), the European Commission (and the DG Agriculture, in particular) publishes its own evaluation analyses and reports, produces its methodological guidelines and encourages (and funds) the scientific community to carry out independent and rigorous programme evaluation studies (European Commission, 2006; EENRD, 2010). Two overlapping factors may explain this increasing interest for policy evaluation studies. On the one hand, the scientific community has increasingly recognised policy evaluation as a legitimate scientific challenge, also in the specific fields of agricultural economics and rural studies, and has progressively developed a sophisticated toolbox in this respect (Imbens and Wooldridge, 2009). On the other hand, however, policy evolution in these fields has significantly increased the complexity of this evaluation, which has led to the expansion of the amount of evidence policy design needs to better pursue its objectives. In many developed countries (and, in particular, in the EU), agricultural and rural policies have been progressively reformed with the aim of assigning them new and multiple objectives. The emphasis on agricultural and rural policies as multipurpose policies, allegedly aiming at (and/or justified by) the provision of a large set of heterogeneous public goods, will be likely confirmed and reinforced even in the next decade. Multiple and heterogeneous goals, however, make the evaluation of policy effectiveness an even more complex task. Evaluation is expected to look at all the declared policy objectives and to take properly into account heterogeneous territories and farm-agent typologies as well as the interaction with other (mostly non-sectoral) policies pursuing similar or complementary goals (e.g. environmental and regional policies).