Survival Rate by Enrollment Size
In the smallest enrollment group, 5 of 165 were observed closed, for a descriptive survival rate of 97%. The only other observed closure falls in the next-higher enrollment group.
This pattern is consistent with small institutions having less room to absorb enrollment shocks, but six outcomes cannot establish a threshold shape or rule out differences in reporting and institution mix.
How Long Until It's Too Late?
The one-year-decline group contains 1 observed closure among 445 institutions. The three-or-more-year group contains 2 among 186; the five-or-more-year group contains 0 among 47.
The Danger Zone
This is a screening definition, not a validated tipping point. The criteria are easy to monitor, but one observed closure among 93 matching institutions does not justify a claim that survival becomes unlikely or that crossing the threshold should trigger a specific action.
The definition remains useful for organizing a watchlist: is enrollment below 900, and has it declined for three or more consecutive years? Any practical warning system would still need better outcome coverage, threshold validation, and institution-level review.
The current data do not establish an intervention point. They support the narrower conclusion that size and trend are sensible variables to carry into a better longitudinal validation.
Descriptive survival summaries from College Scorecard and IPEDS 2015–2023 data. Decline years = consecutive annual enrollment decreases. Survival = institution still operating as of the last retained filing. No causal or deployment claim is made.