Larger sample size and more accurate data.
The music industry claims that albums which are leaked prior to their release cause them the greatest financial loss: this study demonstrates that this is simply not true:
‘However, according to the research, sales may actually be hurt by going after these [file sharing] sites. Hammond’s findings suggest that piracy itself acts as a form of advertising similar to radio play and media campaigns, where more downloads result in a moderate increase in sales.’
Let’s not hold our breath hoping for the recording industry will admit its error…