A student-to-faculty ratio gets thrown around as shorthand for "how much individual attention will I actually get," and at the most selective schools, the real numbers back that up more than the phrase itself lets on.
The real numbers at three elite schools
Per each school's own official published figures:
- Princeton: 5:1, stated directly on Princeton's own Facts & Figures page.
- Stanford: approximately 5:1, per Stanford's own official Facts site.
- Harvard: 7:1 overall, per Harvard College's own official materials -- but its School of Engineering and Applied Sciences reports a separate, lower 5:1 ratio specifically, a real example of how a school's headline number can mask meaningful variation between its own divisions.
What this actually compares against
National estimates for the average US college student-to-faculty ratio vary depending on the source and year -- commonly cited figures range from roughly 14:1 to 18:1. That range itself is worth being honest about rather than picking whichever number sounds cleanest: different data-collection methodologies (and different points in time) produce genuinely different national averages, and no single figure is universally agreed on the way a specific school's own published ratio is. Even using the lower end of that range, a 5:1 or 7:1 ratio at Princeton, Stanford, or Harvard is meaningfully below the typical national experience -- roughly a third of the ratio, not a marginal improvement.
What a ratio like this doesn't guarantee
A low student-to-faculty ratio describes an average across an entire institution, not a promise about your specific classes. Large introductory lecture courses can still run far above the school's overall number, while small upper-level seminars run well below it -- the published ratio is an institutional average, not a per-class guarantee. It's also worth noting, as Harvard's engineering-specific number shows, that the ratio can vary meaningfully by school or division within the same university, so the headline figure for a large research university may undersell (or oversell) the experience in your specific program.
What this means for you
- Compare a specific school's official published ratio, not a rough estimate from an aggregator site -- Princeton's, Stanford's, and Harvard's own sites all state their number directly.
- Don't treat the national average as one settled number -- it moves meaningfully (roughly 14:1 to 18:1) depending on the source, so use it as a general benchmark, not a precise comparison point.
- Ask about ratios within your specific intended school or department, not just the university-wide figure -- Harvard's own engineering-specific 5:1 shows a single university-wide number can differ from what a specific division actually offers.
- A strong ratio is one input into fit, not the whole picture -- it says something real about class sizes and faculty access on average, but not about teaching quality, advising culture, or how accessible faculty actually are outside the classroom.