On the reliability of software piracy statistics

摘要

The Business Software Alliance (BSA) changed its consultant and methodology for measurement of software piracy in 2002–2003. Based on a review of the methodology and empirical analysis, I conclude that the change had systematic effects on published piracy rates. The trend rate of decrease of piracy rates fell from 2.0% points per year to 1.1% points per year. The impact of the change was larger among developing than advanced countries. Software usage in countries where usage was not directly measured was projected on the basis of national income. Any government policy or academic study using the BSA software piracy statistics should take account of the BSA’s change in methodology.