My interview was a later in October and the director of admissions very specifically said that we were not guaranteed to get a decision by the end of the calendar year. Someone referenced
this page, where it says they will let us know by the end of December. She made a note to herself to change the language on that page (but it has not changed).
On the admissions process page, it says:
"After your interview, the Admissions Committee will meet to review and discuss your application. Applications are under continuous review, which allows for admissions to be made throughout the interview season until the class is filled.
All final decision notifications, including acceptance, wait list, and unsuccessful application, will be sent to applicants by early April."
Which is also inconsistent with the page I linked... Anyway, all I can say is that someone in my interview day specifically asked if we would receive a decision before the end of the calendar year and the director of admissions very clearly said no. However, I think odds are those of us who interviewed before November are much more likely to know before the end of the year.