Files
Abstract
There is a wide range of evaluation methods. On the basis of which criteria should one method
be chosen? On what scientific foundations are the results of numerous evaluations based? How
can reliability and empirical validity be tested? The relevance of such questions is heightened in
new fields of action such as agri-environmental policy. This paper aims to demonstrate that
theoretical advances on level and types of evidence (existence, causality, effectiveness) can help
resolve these issues. The main evaluation methods are classified into three main categories,
according to their main goal (to learn, measure, understand) and linked to the debate on types
of evidence. The analysis is illustrated by comparing evaluation methods in the field of agroenvironmental
policies and farm advisory services. Attention is drawn to the shortcomings of
each method with respect to corroborating facts as well as existing complementarities and
trade-offs between methods in terms of empirical validity.