Not sure what you are looking for. The CDS form itself asks for information regarding the first-time, first-year, freshman students who enroll in the fall. All of the admission, retention, and grad rate data are measured by following this cohort throughout the rest of their time at the school. One example from the CDS website/instructions:
"Retention Rates
Report for the cohort of all full-time, first-time bachelor’s (or equivalent) degree-seeking undergraduate students who entered in Fall 2017 (or the preceding summer term). The initial cohort may be adjusted for students who departed for the following reasons: death, permanent disability, or service in the armed forces, foreign aid service of the federal government or official church missions. No other adjustments to the initial cohort should be made."
So kids who don’t enroll in the fall are off the CDS books.
As to why, I’ll let the market leader Northeastern speak on this:
“The N.U.in Program offers well-qualified applicants—to whom we were not able to offer admission in the fall—the opportunity to join our community and begin their time at Northeastern with experiential education.”