Pourquoi les économistes sont-ils en désaccord ? Faits, valeurs et paradigmes. Revue de la littérature et exemple de la fiscalité

Economists disagree. They do not agree on whether they disagree, or on why. Some think that they disagree mainly over values, but some studies show that they also disagree over facts. Economists seem to be excessively confident in their estimation of parameters, a classic expert bias. Building on the example of taxation this article points out that the classic distinction between facts and values is too simplistic. Concerning distributive issues, there is obviously no value-free measure : what is measured is often the difference from a norm, neither entirely normative, nor merely descriptive. Moreover, parameters have meaning only within a given model. The disagreement concerns the model itself, or the choice of appropriate simplifying assumptions. This choice also mixes normative and positive issues.