090d. Why Peter Gamma from www.petergamma.org does not know if the scientific data of Rob ter Horsts more than 100 smartwatch accuracy tests nor the scientific data in accuracy validation papers about consumer grade heart rate monitors will be reproduced convincingly by other scientists?

A key scientific paper in this context is this one:

Lin LI. A concordance correlation coefficient to evaluate reproducibility.

Biometrics 1989

;45:255-68. 10.2307/2532051

This paper has been cited 8580 times to this date:

https://scholar.google.com/scholar?hl=de&as_sdt=0%2C5&q=A+Concordance+Correlation+Coefficient+to+Evaluate+Reproducibility&btnG=

Why has this paper been so often cited? It is a key paper which say something about what is required so that heart rate measurement are reproducable at the highest accuracy level. These requirements are:

• A three lead (or 3 channel) ECG device.
• The Mason-Likar electrode placement.
• ECG-based HR has to be determined by visual assessment of a trained research personnel.

We find hardly any PPG devices from:

• iWorx

• Biopac

• Adinstruments

• g.tec medical

All of these manufacturers of devices which are suitable for scientific studies offer devices with 3 ECG channels or more which cost several 1 000 of dollars.

And neither Rob ter Horst’s 100 smartwatches

nor

the other heart rate monitors listed in these papers:

090. Review of Accuracy Studies of Consumer Grade Heart Rate Monitors: Methods, Testing Protocols, Reference Devices

fullfill the requirements for gold standard for heart rate measuremens which are indicated above.