Table 3. . Minimum and best evidence requirements of safety and effectiveness for each DHT evidence tier.

Broad functional category	Evidence tier	Contextual factors to determine risk and minimum vs best evidence requirement	Minimum evidence requirement	Best evidence requirement
Self-directed health management	Tier 1	Not applicable	The DHT provides valid, accurate, up to date information.	Empirical data from users on perceived behavior change or health improvement, typically a pre- / post-study design within users.
Professionally directed diagnostic and prognostic health management	Tier 2	Best evidence may be required if: The DHT is ‘first-in-class’ Lack of similar platforms High consequences of inaccurate information	Initial validation: Accuracy and precision of the DHT against a well-established reference (gold) standard. Able to detect clinically relevant differences.	RCT demonstrating that use of the diagnostic DHT improves patient outcomes. If measurement of patient outcomes not feasible (e.g., long disease latency), then studies evaluating changes in clinician diagnostic impression and clinician behavior may be acceptable.
Professionally directed preventative and therapeutic health management	Tier 3a	Best evidence may be required if: The DHT is ‘first-in-class’ Lack of similar platforms High consequences of ineffective intervention	High quality observational or quasi-experimental studies with an appropriate comparator and relevant patient outcomes. Outcomes may include patient reported outcomes, engagement with the healthcare system, or clinical data.	RCT demonstrating clinical efficacy. Study may be conducted in a selected population. Surrogate outcomes and short-term follow-up may be acceptable.
	Tier 3b		RCT demonstrating clinical efficacy. Study may be conducted in a selected population. Surrogate outcomes and short-term follow-up may be acceptable.	Additional RCT demonstrating clinical effectiveness and generalizable to the patient population and health systems of interest. Demonstration of durability of treatment effect to pre-established timepoint guided by expert opinion. Captures patient-centered outcomes and treatment is compared with best or most common active comparator.

DHT: Digital health technology; RCT: Randomized controlled trial.