* Specific Program: Top-tier programs like Harvard, MIT, Stanford, Princeton, and Berkeley have extremely low acceptance rates (often single digits, sometimes below 5%, and even lower for certain specializations). Less selective programs will have significantly higher acceptance rates.
* Applicant Pool Strength: A year with exceptionally strong applicants will naturally lead to a lower acceptance rate, even at the same program.
* Specialization: Some areas of mathematics are more competitive than others (e.g., theoretical computer science often has a very competitive applicant pool).
* Funding Availability: Programs with limited funding will have lower acceptance rates as they can only accept a certain number of students they can support financially.
Instead of a single number, think of a range. Highly selective programs might be below 10%, while less selective programs could be 20% or even higher. Many programs don't publicly release their exact acceptance rates.