<p>Fabrizio,</p>
<p>Actually, there have been a number of studies done to support the relationships between affluent families/students and their strategies to apply early to colleges. Without getting into a debate on causal relationships and statistical correlation, its evident that Harvard and Princetons decisions were based on what they viewed to be an inequitable situation. Shirley M. Tilghman, Princetons president, noted that early admission advantages the advantaged. She stated that although they have tried hard to create more diversity in their pool of early program applicants, they have not succeeded and concluded that a single admission process is necessary to ensure equity for all applicants.</p>
<p>The best book I have read relevant to this topic is The Early Admissions Game, written a few years ago by a couple of professors from Harvards Kennedy School of Government and a former associate dean of admissions at Wesleyan University.
Reference: <a href="http://www.hup.harvard.edu/catalog/AVEEAR.html%5B/url%5D">http://www.hup.harvard.edu/catalog/AVEEAR.html</a></p>