Sorry I confused you. Whatever the definition of 'academic potential' may be, it most certainly doesn't mean the potential to become an academic.
Academic potential is divined by looking at a student's academic record from high school, a student's expected grade trajectory given their socio-economic status, location or calibre/ reputation of school, or other elements such as whether English is their first language, and standardised test results. It can also be glimpsed in the personal interview part of the application process (sometimes a personal interview is optional, though). On top of all that, applicants are asked to provide references from past teachers as part of the application portfolio.
The hope is that admitted students in Ivy League universities or colleges will contribute to the undergrad environment through academic prowess, eagerness to develop their academic ability across a broad range of studies, curiosity, and determination to master their topics of study; through varied perspectives born of diverse experiences, cultures, or heritage, and also through the personal qualities each one brings to the mix.
Obviously, nobody can predict exactly how an admitted student will perform academically or in any other way over their four years of undergrad studies. Some students will do far better and some far worse than anticipated. Some will transfer to another university. Some will drop out. Admissions committee practice an art, not a science.