On account of the leap second, I kept comparing ABC’s clock on the ball drop to the clock on my set-top box which gets its time from the cable company. How do I know the latter was accurate? Every day at 1 PM, the CBC broadcasts the “Dominion time signal” and I had compared them yesterday and the cable time was right on. Whether I could have accurately detected a one second difference (what I was hoping to see) is perhaps questionable, but a 7 second difference in unmistakable. And the ABC clocks 0:00 coincided exactly with the ball hitting the ground and lighting up. Clearly ABC knew this was going to happen and adjusted their clock accordingly.
Our cable box turned 12:00 several seconds before the countdown at the Space Needle reached zero. The countdown may not have even started until several seconds after the clock showed midnight.
I also noticed ABC did not match my cable box or phone.
My guess is, it was the “seven-second delay” that pretty much all live shows have, so they can censor dirty words and black out things like nudity. (The ABC clock, generated in the studio, would not need a delay.)
Besides - “only” seven seconds? I have AT&T U-Verse, which has an inherent 15-second delay on all shows, so midnight was 22 seconds late. The Sky News coverage from London that goes through Roku was almost two minutes delayed.
Also, it appeared that the “official start of the ball drop,” when the mayor pushes down on a giant ball one minute before midnight, did not happen as the singing of “Imagine” ran long.
Aren’t live broadcasts sometimes run through a several second delay in case they have to beep profanity, etc.?
eta: NINJA’d
It’s more likely compression pipeline latency. It’s possible to compensate for this when broadcasting the station time etc, but when it comes to coverage of a public time event (such as New Year’s eve), there’s no way to compensate.
Seems like a reasonable explanation on the East Coast, but what about West Coast viewers who were watching a recorded show? 
AKA, in the case of CNN, the “Kathy Griffin Rule.” 
Why go to the trouble of moving everything back 7 seconds in the program/commercial line up?
Ah, mystery explained. BTW, NBC seemed to have a 14 second delay.
Maybe it was just trying to delay until when Trump takes office.
When CNN rebroadcast their NYE NYC celebrations on the west coast, CNN was six minutes early counting down to midnight!
I have a cable box, a Roku and an OTA, and I can also watch on my phone. If I decide to watch the same program on all four devices, it comes in at four different times.
If my ball had been seven seconds late I’d still be single.
When I had Uverse, it used to annoy me that if I turned the same program on three different TVs, there could be as much as a 10 second spread between them.