Guys I think no answer yet for ED applicants (even for those waiting a month+) simply means 'maybe', I don't think it guarantees a ding. I believe the adcom notifies you once the decision is made, I don't think they wait till a notification date to ding people, which the spreadsheet supports.
I remember reading that Columbia has 2 people look at apps. Either one can rec for interview. So if the first passes on your app, the 2nd can still rec for interview. If you have been waiting over a month, perhaps the first person passed on your app, but the 2nd reader might rec for interview. Keep your hopes up!
Also, for those that have interviewed and have not heard back yet, I think adcom is probably waiting to see what other applicants they come across that might fall into the same profile to compare us with. Those that interviewed and were admitted only a few days later probably had such strong profiles that adcom knew they didn't need to wait to compare them to others.
Just my 2 cents.