The primary reason is there are few accepted digital biomarkers that indicate whether a person is getting better or worse — let alone identify when an intervention is recommended. Validating a digital biomarker can be a huge task. The biomarker must be shown to reliably measure every application in every population where it will be employed. Often thousands of people must be monitored over an extended period to validate a single digital biomarker for a single condition. But that is not the only challenge. Currently, most of the scientific work on this issue is conducted in highly tailored studies tying a specific biomarker to a specific condition in a specific population and often to the action of a specific therapeutic. As a result, the Digital Medicine Society’s Library of Digital Endpoints (aka biomarkers) now has more than 70 distinct measures of activity and 55 measures of sleep. Healthcare providers cannot be expected to apply dozens of different measures of essentially the same phenomenon. These need to be standardized.