Five anchors are set out in What we are building, what we are not, and why, and here the accuracy of the individual values.
The access
Shiihaa runs in the browser. Anyone with an interface and an internet connection can breathe and measure. No outside account is needed, no recent phone, no second device.
Five conditions we hold every change against:
- No outside platform identity. An account with Shiihaa is enough.
- No outside service at load time. Fonts and program parts sit with us. The one exception is the payment path, because it moves money and answers for chargebacks.
- No recent device. Whatever requires special hardware drops out cleanly on weak hardware.
- Little bandwidth. Load weight is grounds for exclusion.
- After the first visit, the essential part runs without a network.
Shiihaa costs money. The access is designed; the price is not waived.
The measuring
What gets measured is the flow sound of breathing, taken with the microphone already built into the device. The band from 150 to 2500 hertz is evaluated. Out of it come breathing rate, the ratio of inhalation to exhalation, the regularity and the depth.
Where a connection to a heart sensor over Bluetooth exists (desktop, Android, Chromium browsers), heart rate variability is measured as well. On the iPhone that interface is missing in every browser, because all of them build on the same foundation. There we say so in the interface and leave the measurement out. A substitute method that is weaker than the promise is out of the question.
The numbers
Every number shown has been measured. Its accuracy determines how it is displayed.
The breathing rate is given as a whole number. One decimal place would be covered only after some 24 minutes of measurement, and a measurement window holds eight breaths. The ratio of inhalation to exhalation is given in half steps. Breathing depth is given as a word, because it is the least well supported value.
Before an exercise and after it, we show a difference only when it is larger than the spread of the measurement itself. Where that is not the case, a sentence stands in place of a number. With fewer than two breaths on record, no result is shown.
There is no rating number from 0 to 100. Such a number sums up values of differing accuracy and hides the uncertainty.
What is missing
We have no comparison measurement against a reference device. As long as that is missing, we state no accuracy figure and no word such as validated. We are working on it and will publish the result with numbers, even if it turns out inconvenient.
Claims of effect rest on studies with a verifiable reference. Where the reference is missing, the claim goes.
The standard
Shiihaa is an instrument. An instrument shows what it measures.