The current debate on trade liberalization is accompanied by an increased concern about environmental and food safety issues leading to frictions of different country groups under the World Trade Organization (WTO). This discussion paper aims at shedding more light on some of the issues in the...

Haavelmo's seminal 1943 paper is the first rigorous treatment of causality. In it, he distinguished the definition of causal parameters from their identification. He showed that causal parameters are de fined using hypothetical models that assign variation to some of the inputs determining...