As a measure of economic growth GDP (and its components) need to be handled with care, for the interpretative fallacies to which they can lead, especially over long periods of history. The book devotes ample space to the dangers that economic historians using quantitative evidence normally face, related both to the conceptual content of the data used in their studies and to the difficulty in extracting information from old and disparate historical sources. Historical series for Italy have been reconstructed over the last 40 years by different scholars – some of them member of our research group – using heterogeneous methods and referring to different time ranges and sectors. In order to obtain new national accounts series from 1861 to the present, we had to reconcile the various available series and translate them into the language of a national accounts standard.
The sources and methods used are thoroughly described in the book and are accessible, in the form of data spreadsheets, in the Historical statistics section of the website of the Bank of Italy.