Eric Boorstin, a senior at Princeton, just filed his senior thesis, Music Sales in the Age of File Sharing. The thesis includes a clever study of the impact of Internet usage on CD sales. This is a twist on previous studies, which have tried to correlate CD sales to usage of filesharing. The tradeoff here is that although Internet usage is one step removed from filesharing, the data on Internet usage are much more detailed and much more reliable than the data on filesharing usage.
Eric worked from two datasets. The first dataset came from SoundScan, and gave him aggregate sales of CDs, on a week-by-week basis, for many separate metropolitan areas in the U.S. The second dataset came from the U.S. Census Bureau, and contained data on population, income, and Internet usage, broken down by age group and geographic area. The census data came from 1998, 2000, and 2001. Combining these datasets, he ended up with data for CD sales, age group demographics, income, and Internet adoption, at three different points in time, in ninety-nine separate metropolitan areas in the U.S.
Eric took these datasets and did a regression to determine the correlation between Internet adoption rate and CD sales, broken down by age group. He controlled for differences in personal income. (For more methodological details, see the thesis.)
For people in the 15-24 age group, he found a significant negative correlation between Internet adoption and CD sales. For people in all of the age groups older than 25, he found the opposite