Most open-access American colleges assess incoming students to decide which math and English courses they may enter. That short assessment often determines how long a degree takes.
What placement testing is for
Colleges enroll students with widely varying preparation and need some basis for deciding who is ready for credit-bearing coursework in each subject.
Historically this was a standardized placement exam taken shortly before enrollment, sometimes with little notice and no opportunity to prepare.
Students scoring below a cutoff were assigned to developmental courses, also called remedial, which charge tuition and consume time but generally carry no credit toward the degree.
Why the sequence is where students are lost
Developmental placement often means more than one course before the credit-bearing class begins, creating a sequence that can span several terms.
Each additional term is another point at which a student can meet a scheduling conflict, a financial problem or a family event and stop attending.
The cumulative effect is that completion falls with each added step in the sequence, independent of whether any individual course was taught well.
The critique of the test itself
A single timed exam taken cold measures current recall as much as capability, and students who have been out of school for years are disadvantaged relative to recent graduates.
Many students do not know the test is consequential, so preparation is uneven in a way that tracks how much guidance each student received beforehand.
Comparisons of placement results against high school records have suggested that a meaningful number of students placed into developmental courses could have passed the credit-bearing course directly.
What replaced the single cutoff
Multiple measures placement uses high school grades, prior coursework and sometimes self-reported information alongside or instead of a test score.
Corequisite models place students directly into the credit-bearing course while adding a support session, replacing a sequence of prerequisites with concurrent help.
Several states have mandated one or both approaches, and adoption elsewhere is institution by institution, so the policy a student meets depends heavily on where they enroll.
The open questions in the shift
Supporters point to more students completing the credit-bearing course, since removing steps removes exit points regardless of instruction quality.
Others raise concerns about whether support sessions are sufficiently resourced, and whether passing standards hold when the underlying preparation gap is unchanged.
Because policies differ by state and institution and are still being revised, prospective students are best served by asking a specific college's advising office how placement works there.