What is CAS? The LSAC service almost every law school makes you use

CAS exists so that you send your materials once instead of once per school. Transcripts, letters of recommendation and the rest go to LSAC, which assembles them into a standardized report and delivers a copy to each school you designate.

What is in it

Transcript summarization is the part worth understanding, because it is not neutral. LSAC recalculates your undergraduate GPA on its own conversion, which can differ from the GPA your university reports — most visibly for repeated courses, some pass/fail arrangements, and grades from institutions with unusual scales. The number law schools compare is the LSAC one.

Cost and duration

Five years is generous and it is worth knowing about, because it means someone who subscribes, applies, and then defers law school for a couple of years does not usually start over. It also means there is no advantage to delaying the subscription — start it when you begin collecting transcripts.

Who has to use it

In practice: assume you need it, then check the exceptions. If your entire list is Canadian, or is made up of the specific U.S. schools that opt out, you may not — but that is an unusual list.

Start it earlier than feels necessary

The slow part is not LSAC. It is every registrar you ever enrolled with. A transcript from a community college you attended one summer, or from a study-abroad program, takes as long as it takes — and your report is not complete until all of them have arrived and been summarized.

Request every transcript at the same time, from every institution, including the ones you think will not matter. Then the waiting happens in parallel instead of one discovery at a time.