Quality marks on your readings

Every reading in the Vault carries up to four marks. They say what kind of source took it.

The marks

• Four, Reference: a device built for that measure, like a chest strap for heart rate or a cuff for blood pressure. Only on that measure: a cuff's other readings count as Sensor.
• Three, Sensor: a sensor worn on the body, like a watch, a ring or a smart scale.
• Two, Estimated: worked out by an algorithm, or from your phone's motion.
• One, Manual: a value typed in by hand.
• None, Unknown: Soma can't tell what took it. The reason reads Source not recognised.

A short reason sits next to the mark, like Chest strap, Cuff, Ring, Glucose sensor, Scale, Wrist sensor, Phone motion, Entered by hand or Worked out by an algorithm.

What they don't say

The marks describe the source. They don't say whether a number is right. A good ring worn loosely can read worse than a phone, and a typed weight from a good scale is as true as any. If a typed value looks wrong, see A number you typed looks off.

Why it matters

When two devices disagree, the marks help you decide which to trust. Doubled or mismatched readings shows how to tell Apple Health which one comes first.