flyingturtle wrote:Just to expand on that a bit; one of the most important questions asked by election officials at the end of the election / before the actual counting begins, is...."How many votes have you got in that there box, Bud?"seb146 wrote:Every election, I wonder the same things:
how can media outlets call races with only like 5% or 6% of ballots counted?
how can media outlets know how many total ballots have been cast to say there are 5% or 6% of ballots counted?
Your second question is easy. Ballots get counted as they are dropped into the box, or as they arrive by mail. So you know the total number of votes.
It tells them several things.
1) If every other district is showing a turnout of 65%, and your box has substantially more (or less) than that number, they need to ask why. Of course there are certain neighborhoods that regularly differ from the national average, in which case historical data will often back this up.
This year, with Covid and mail-in ballots, the numbers are less predictable.
2) It gives the people at the count a target to work to. Putting it simply; if I say I have 1000 votes in my box, but the counting center comes up with 500 votes for candidate A, and 430 for candidate B, then we already have 70 votes "missing". Either that, or I have messed up the math and should have declared 930 as the box total.(¹)
In fact, in my experience it doesn't even get to the stage of splitting the votes between candidates; stage 1 is simply verify that the count center has received 1000 pieces of paper.
Again, this only applies to votes cast in person. Mail-in votes will be counted as they arrive, most probably...
As to exactly how & when this nugget of information is shared with the media; that's going to vary.
Then again, the last time I contributed my experiences to a thread on voting procedures, my contribution was dismissed because...
That's the beauty of the internet, anyone can claim to be anything.
So there you have it; I could be anybody. Or nobody.

(¹) The box total should correspond to the number of ballot papers issued (excluding any that are "spoilt"). This is arrived at by noting the serial number of the first ballot paper issued (A), and the serial number of the next ballot paper remaining at the end of poll (B). (A) minus (B) is your total issued.
At the close of poll, you pray that the totals match up, and that you didn't hand out a ballot paper to someone who simply stuffed it in their pocket and walked out with it.