Hello, I’m curious…if a college says their ED notification date is by Dec 15th, do applicants ever get notified earlier? Or, do colleges wait until the very last day to notify?
Thanks!
Unless a school is on rolling decision, usually they release all decisions together.
Some colleges use 12/15 as a placeholder, and toward the end of November, they may update with an earlier date that’s a couple days earlier. Ivy League schools seem to do this every year. However, on that date, each college release its decisions simultaneously. There are exceptions.e.g. UMich promises decisions on EA applications “by 12/24” but generally release a large chunk a few days early (but not at the same time) followed by dribs and drabs over the next several days.
Generally, they’ll notify you when they’re good and ready 
It’s nothing to stress over, because you have absolutely no control over it. Just be prepared for regular admissions. I usually recommend against ED, because students never get sufficient time to shop around. Don’t sign anything unless you know it’s the right fit and you can afford to go there. If they decide to lowball your financial aid, you can still tell them to shove it.
Yes, sometimes.
My son heard back from an early action school (SUNY Binghamton) on something like either 11/30 or 12/1. It had promised to notify applicants by January 15th.
He heard back from his early decision college (Williams) a full week before the listed date of 12/15.
In Binghamton’s case, they released their decisions in batches. There was no notice until their email once the decision had been made. Some people heard back earlier than my son did, and other people heard later than he did.
Williams notified applicants of the exact release date and time about a week before it happened, and all ED applicants were notified at the same time.
This is the type of thing, that with perspective, you will look back and wonder what the big deal is.
They will let you know on or around that date…would suggest you have some other apps ready to go if necessary.
Last year it was Thurs. Dec. 14th for Ivies/their equivalent. I’m going to selfishly hope for Dec. 13th this year–because if it’s the 14th my kid (and her teammates) will all be at a sports meet. And that’s probably NOT an ideal time to get the news, one way or another, LOL! Is that too much to hope for?! 
Actually, last year (and every year), it depended on the college. Cornell released on the 11th and Stanford releasedon the 8th, as examples.
That’s good to know–I always thought the Ivies agreed on a day and released decisions at the same time!
They do for RD (the same day, not necessarily the same time), but not for ED/SCEA.