Table 1.

Final taxonomy of technical characteristics of health conversational agents (CAs) with 18 dimensions and corresponding characteristics; when applicable, the references indicate from which publications the characteristics were adapted.

Level 1 (perspective) and level 2 (dimension)		Level 3 (characteristic)
Agent appearance
	Personality of CA	Simple Complex
	Embodiment [27]	None Avatar Physical
	Application technology	Virtual reality Augmented reality Vocal Normal
	Intelligence framework [14,24]	Rule based Self-learning
	Sentiment or emotion detection [14]	Yes No
Setting
	Context [14,23]	General-purpose Domain-specific
	Service duration [9,24]	Ad hoc supporters Persistent companions Temporary advisors
	Human involvement	Dyad Triad Quadriad
Interaction
	Input mode and output mode [14,23]	Written Spoken Visual Hybrid Haptic
	Service channel [14,23]	Smartphone-embedded Software Social media Website (web-based) Smart speaker
	Device	PC Mobile device Both Other
	Language [14]	Single language Multilanguage
	Integration mode	Stand-alone Part of a system
Data processing
	Internet access	On the web Offline
	Hosting [14]	Local Outsourced Other
	Data exchange with third-party device or service	Access Storing Both None
	Data privacy	Privacy policy Data encryption Both Nothing