Table 2. . Overview of evidence tiers for assessment of DHT safety and effectiveness.

Broad functional category	Potential risk to patients	Evidence tier	Functions	Examples
Self-directed health Management	Low risk	Tier 1	Personalized health information for use by the end-user not intended for professional consideration	Mobile health applications available for individual use without clinician involvement. Personalized health information for home use, electronic diaries, or risk assessment tools that can be delivered via Cloud, Internet, or App. Wearables and other ‘smart’ devices for personal use (e.g., fitness trackers, apps that utilize smart watches)
Professionally directed diagnostic and prognostic health management	Moderate risk to high risk	Tier 2	Diagnoses a specific clinical condition and/or guides diagnosis or management decisions through diagnosis or prognosis. DHT use is directed by a medical professional or provides information that would be utilized in consultation with a medical professional.	DHTs with active monitoring that automatically records data and transmits it directly to healthcare professional for clinical decision making (e.g., sensor worn on the body), or monitoring for potentially serious conditions. DHTs in this category may provide immediate feedback to end-user but have the potential to trigger consultation with clinicians (e.g., App for atrial fibrillation monitoring).
Professionally directed preventative and therapeutic health management	Low risk to moderate risk	Tier 3a	Preventative health behavior management with professional involvement	Prescribed behavior change technologies (e.g., smoking cessation, weight loss, insomnia.)
	Moderate risk to high risk	Tier 3b	Therapeutic. Directly provides treatment or acts as an adjunct to other interventions for a diagnosed clinical condition	Mobile applications that deliver a therapeutic intervention (e.g., CBT for behavioral health); DHTs that guide treatment or medical interventions such as wearables that detect periods of apnea during sleep and alarms to rouse the person. Software that creates 3D reconstruction images and determines location

CBT: Cognitive behavioral therapy; DHT: Digital health technology; 3D: Three-dimensional.