@article{Blanco:6674,
      recid = {6674},
      author = {Blanco, Maria and Cortignani, Raffaele and Severini,  Simone},
      title = {Evaluating Changes in Cropping Patterns due to the 2003  CAP Reform. An Ex-post Analysis of Different PMP Approaches  Considering New Activities},
      address = {2008},
      number = {692-2016-47491},
      series = {Contributed Paper},
      pages = {15},
      year = {2008},
      note = {Replaced with revised version of paper 02/22/08.},
      abstract = {There is a growing interest on models able to anticipate  farmers' response to agricultural and
environmental policy  changes. The Positive Mathematical Programming (PMP) method  is being
extensively used for evaluating the likely impacts  of policy interventions. This paper evaluates  the
capability of three different PMP approaches to  forecast changes in cropping patterns due to the 2003
CAP  reform: the standard approach (Howitt 1995, Arfini and  Paris 1995), the maximum entropy
approach (Paris and Howitt  1998) and the Röhm and Dabbert approach (2003). However,  neither of
those approaches allows for activities  non-observed in the base situation. An additional approach  is
therefore suggested to consider new activities already  present in the post-reform situation.
These approaches have  been tested in an irrigated area of Central Italy. All  models have been
calibrated to the pre-reform situation and  then the 2003 CAP reform has been simulated and  model
results have been compared with observed cropping  patterns. Even if all models calibrate perfectly,
response  behaviour depends on the selected approach. Compared to the  standard approach, the Röhm
and Dabbert approach shows a  too wide substitution between crops belonging to the same  group; and
the maximum entropy approach performs better  only when prior information is considered. The
extended PMP  version proposed in this paper depicts a more realistic  picture of post reform cropping
patterns.},
      url = {http://ageconsearch.umn.edu/record/6674},
      doi = {https://doi.org/10.22004/ag.econ.6674},
}