Harvard student notes are cited more frequently than notes by Yale or Stanford students by a considerable margin, according to Eugene Volokh at the Volokh Conspiracy.
In a citation study conducted by Volokh, using notes published from 2001 to present, Harvard comes out way ahead — even taking into account the smaller number of student notes published at Yale (78% of Harvard) and Stanford (40%). Some commenters (from Stanford or Yale?) raise objections.
It’s unclear from the initial post whether only law review notes are included, or notes from other journals at the three schools as well, but Volokh’s own comment implies that it was just the big three. He promises additional data in the future.