It appears that it may well be:
Among the most cited research on the subject — a paper by economists from the RAND Corporation and Brigham Young and Cornell Universities — found that “strong evidence emerges of a significant economic return to attending an elite private institution, and some evidence suggests this premium has increased over time.” Grouping colleges by the same tiers of selectivity used in a popular college guidebook, Barron’s, the researchers found that alumni of the most selective colleges earned, on average, 40 percent more a year than those who graduated from the least selective public universities, as calculated 10 years after they graduated from high school. Those same researchers found in a separate paper that “attendance at an elite private college significantly increases the probability of attending graduate school, and more specifically graduate school at a major research university.