Table 1.

Characteristics of the conversational agents evaluated in the included studies

First author, year	Type of communication technology; type of conversational agenta	Dialogue managementl	Dialogue initiative	Input	Output	Task-oriented
Fitzpatrick et al. 201719	Platform independent appb	Frame-based	Mixed	Written	Written	No
Tanaka et al., 201720	Windows computer app; ECAc	Finite-state	System	Spoken	Spoken, written, visual	Yes
Miner et al., 201626	Mobile device app	Agent-based	User	Spoken	Spoken, written	No
Ireland et al., 201621	Mobile device app; chatbotd	Frame-based	Mixed	Spoken	Spoken, written	No
Rhee et al., 201428	SMSe	Frame-based	Mixed	Written	Written	No
Hudlicka, 201324	Web browser app; ECAf	Frame-based	Mixed	Written	Written	No
Crutzen et al., 201127	Windows computer app; chatbotg	Frame-based	Mixed	Written	Written	No
Philip et al., 201722	Windows computer app; ECA	Finite-state	System	Spoken	Spoken	Yes
Lucas et al., 201735	Multimodal platform; ECAh	Finite-state	System	Spoken	Spoken	Yes
Philip et al., 201423	Windows computer app; ECA	Finite-state	System	Spoken	Spoken	Yes
Beveridge and Fox, 200625	Telephone and web browser appi	Frame-based	Mixed	Spoken	Spoken	Yes
Black et al. 2005,29 Harper et al. 2008,30 Griol et al., 201331	Telephonej	Finite-state	System	Spoken	Spoken	Yes
Levin and Levin, 200632	Telephonek	Finite-state	System	Spoken	Spoken	Yes
Giorgino et al. 2005,33 Azzini et al. 200334	Telephonei	Frame-based	Mixed	Spoken	Spoken	Yes

Abbreviations: app: application; ECA: Embodied Conversational Agent; SMS, Short Message Service

^aType of conversational agent considered unspecific, where not ECA nor chatbot;

^bWoebot, Woebot Labs: instant messenger app, platform independent;

^cAutomated skills trainer developed from MMDAgent (http://www.mmdagent.jp);

^dHarlie the Chatbot (http://www.itee.uq.edu.au/cis/harlie);

^emASMAA, an extension of TRIPS (The Rochester Interactive Panning System);

^fVirtual Mindfulness Coach;

^gBzz Dutch chatbot for Windows Live Messenger;

^hSimSensei Virtual Agent, based on the MultiSense perception system, a multimodal sensing platform which fuses information from web cameras, the Microsoft Kinect and audio capture, and processing hardware (http://multicomp.ict.usc.edu/? p=1799);

ⁱHOMEY project – home monitoring through an intelligent dialogue system (http://www.openclinical.org/dm_homey.html#);

^jDI@L-log: although the system allows for dual tone multi frequency input this is rarely used, as all interactions can occur via spoken language;

^kPain Monitoring Voice Diary, developed by Spacegate, Inc;

^lNot objectively reported in the paper, but inferred from descriptions of the CA, sample dialogues, or other published material on the system