Evidence-based economics: issues and some preliminary answers

This paper presents an outline of a methodology of ‘evidence-based economics’. The question whether an economic statement is evidence-based must be answered on three different levels. The first level concerns measurement: it asks whether claims made about economic quantities such as inflation, unemployment, growth or poverty are justified by the data and measurement procedures. The second level concerns induction: it asks whether claims made about the relations between economic quantities (such as ‘number of babies born predicts growth’, ‘change in money causes change in monetary income’, ‘non-borrowed reserves can be used to control the interest rate’), are justified by the inference procedures. The third level concerns idealisation: it asks whether the quantities and relations selected are justified by the stated aim of the inquiry. The paper provides a discussion of these three types of investigation and of some solutions that have been offered.