Our goal in enabling publishers to display averages is to give an accurate view of the likely number of people who will view your video or stream, without ensnaring publishers into a lot of mathematical settings to tinker with in their campaign set up.
We take the average of the last six months of your videos for YouTube. or streams for any data we have.
For Twitch, we can only get the data from streams you've done since signing up for Woovit. We take five minute snapshots of the number of viewers and calculate your average concurrent viewers for the last six months, excluding very short streams.
We also are removing very short streams to try to get a more accurate representation. We are experimenting with the right number of minutes to qualify a stream, but it will be ten minutes or under.