The experiment in macroeconometrics

This paper examines the experiment in macroeconometrics, the different forms it has taken and the rules that have been proposed for its proper conduct. Here an "experiment" means putting a question to a model and getting an answer. Different types of experiment are distinguished and the justification that can be provided for a particular choice of experiment is discussed. Three types of macroeconometric modelling are considered: the Cowles (system of equations) approach, the vector autoregressive model approach and the computational experiment.