Each circle in the HealthScore represents a different measurement and all of these are combined to give you an overall HealthScore:

Outer Circle - Views
This circle will show you how many views your video has had compared to how many people could have viewed it (based on how many followers/subscribers you have on the account you published to).

Middle Circle - Duration
This circle will show you the average view through rate, letting you know if most people stick around to the end of your video or if they jump off a third of the way through.

Inner Circle - Engagement
This circle will show what percentage of people interact with your video, such as commenting, liking and sharing the video. The more people that engage in these actions on average, the better the score.

Green is represented as being "On Target"

Amber means "Not so good"

Red says your asset is "Way off"

The measurements used to calculate whether your circles achieve a green, amber, or red rating are:

Outer Circle - Views
On target: >10%
Not so good: 5-9%
Way off: <5%

Middle Circle - Duration
On target: >70%
Not so good: 31-70%
Way off: <30%

Inner Circle - Engagement
On target: >10%
Not so good: 5-9%
Way off: <5%