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Buffer Rate Vanity Metrics in Video

Buffer Rate Vanity Metrics in Video

Our team talks to publishers and media companies daily and one theme that constantly comes up is the 1% buffer rate. By this I mean, the publisher says that they are tracking the amount of time spent buffering versus watching video and that the rate of buffering to video watching is 1% or some variation around this low rate.

buffering seconds/video viewing seconds

So is 1% good? It certainly sounds good on the face of it. So video delivery is solved right?


Not so fast…

This metric means that for each second of watching video, you have a 1 percent chance of the video stalling and buffering.

So if you watch only 1 second of video, then you will have a great experience 99 times out of 100.

The problem: You don’t watch just 1 second of video

What this misses is that a 1 percent chance of buffering every second leads to a 26% chance of buffering after 30 seconds. The laws of probabilities mean that over 30 seconds you have .99³⁰ = 74% chance that video will not buffer/stall.

When viewed this way, every 30 seconds of video viewed, 1/4 of people will experience some video buffering/stalling. That turns this 1% vanity metric into something to be much less proud of.


Let’s do better

The real metric that you should care about is what percentage of users have these buffer/stall events happen to them. The percentage of users that essentially have a poor experience with your content.

Bad Experiences/Total Experiences

If looked at this way, a 1% buffer rate is actually a 25% bad experience rate if your videos average 30 seconds.

Backing out the buffer rate

If you only have a buffer rate, what should you be targeting to ensure that 97 out of 100 people have a good experience with your video?

The answer ends up being a buffer rate of 0.1%. The rate needs to be shifted an entire order of magnitude to ensure that only 3% of experiences are bad.

Now that might not be possible and is likely why the buffer rate numbers don’t at all match up to the experiences that we have when watching video, but it is a goal and helps keep in perspective that a 1% buffer rate only means video success for 3 out of 4 end users.

1% buffer rate = 1 out of 4 people have a bad experience

If you are only measuring buffer rate, make sure to target a rate that actually leads to a good experience.