Conversational agents (CAs), also known as chatbots, are computer programs that simulate conversations with users [1]. CAs are multimodal and can be deployed via messaging apps such as Telegram, Facebook Messenger, and Slack [2]; as standalone apps or websites; or integrated into cars or television sets. CAs may operate using simple text interfaces as the most basic form, as voice assistants, or as embodied CAs that use virtual characters to simulate both verbal and nonverbal human behavior [3]. CAs are multifunctional and can automate a variety of tasks such as provision of information or news, web-based shopping, or as symptom checkers.

Health care is an ideal candidate for CA-delivered interventions [4]. CAs can assist patients by providing timely information [5], support mental health disorder management [6,7], and assist with triage in clinical settings [8,9] by harnessing the increasing ubiquity of smartphones [10] and other digital media [11,12].

CAs are increasingly being used for delivery of interventions focusing on disease treatment, management, and prevention [13]. An important component of such interventions is behavior change. Behavioral change interventions are defined as “coordinated sets of activities designed to change specified behavior patterns” [14]. Most behavior change interventions are complex, comprising the interaction of one or several smaller components, often referred to as behavioral change techniques (BCTs) [15]. A BCT is “an observable and replicable component designed to change behavior” [15], with descriptors as the smallest component compatible with retaining the postulated active ingredients of components designed to alter or regulate behavior, enabling easy coding and extraction of data in the intervention context [15]. Although various BCT taxonomy systems have been developed, BCT Taxonomy v1 (BCTTv1) [16] is widely used to provide a shared, standardized terminology to specify the active ingredients to support behavior change in health care interventions. BCTTv1 consists of 93 distinct BCTs divided into 19 major groups such as “goals and planning” and “feedback and monitoring” [16].

Existing reviews on CAs are largely descriptive and focus on effectiveness [17,18]. Systematic reviews on BCTs found that incorporating certain BCTs in the design of health care interventions increased their effectiveness [17-19]. Examples include action planning to enhance physical activity [20] or self-monitoring to increase physical activity and healthy eating [21]. Given the increasing use of CAs in health care and delivery of behavior change interventions, it is crucial to understand the way BCTs are incorporated in their design, including what BCTs are most commonly used and the behavior they intend to change [22]. By identifying what BCTs are employed, to what outcomes, and for what function according to experimental studies, this review seeks to advance understanding of the types of BCTs used in CAs in health care.

The aim of this scoping review is to identify and present BCTs that have been included in behavior change interventions delivered via CAs. Specifically, the review will try to answer the following questions: (1) Which BCTs are used in CA-delivered interventions in health care? (2) What are the target behaviors the CA in health care aims to modify? (3) What were the theories/frameworks guiding the design of behavior change interventions delivered via CAs in health care? (4) Which BCTs have been incorporated into the effective CA interventions?

This scoping review will follow the Joanna Briggs Institute scoping review guidelines [23] and will be reported in line with the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) reporting guidelines [24].

A systematic search will be performed of both peer-reviewed and grey literature. Peer-reviewed articles will be searched on the following databases: PubMed, Embase (Ovid), and Cochrane Central Register of Controlled Trials (CENTRAL). Grey literature will be identified by searching the first 10 pages in Google and Google Scholar.

The search strategy includes an extensive list of related words and phrases that define “conversational agents,” which was updated from a search strategy used in a previous scoping review on CAs published by our research group [2] (see Multimedia Appendix 1).

All studies retrieved from the searches will be uploaded to EndNote X9 (Clarivate) and further imported to Covidence [25], an online tool to assist in the production of systematic reviews, to facilitate the screening of eligible articles. Screening will be performed in two stages, according to inclusion and exclusion criteria. In the first stage, the titles and abstracts will be screened by two independent reviewers. In the second stage, the full texts of all studies included will be acquired and reviewed by two independent investigators. Discrepancies resulting from any screening stage will be resolved by discussion between the reviewers or by engaging a third reviewer if discrepancies cannot be resolved by discussion alone. Interrater agreement will be determined using the Cohen κ coefficient in which κ≥0.6 (substantial or almost perfect agreement) will be considered to be acceptable [26]. The search and screening processes will be documented using a study selection flowchart [27].

This scoping review will include primary experimental studies on a CA-delivered health care intervention focusing on behavior change. The eligible study designs comprise randomized controlled trials, quasirandomized controlled trials, cluster-randomized trials, controlled before-and-after studies, uncontrolled before-and-after studies, interrupted time series, pilot, and feasibility studies. Nonexperimental study designs, including observational studies, qualitative studies, reviews, personal communications, editorials, as well as conference abstracts and studies where it was not possible to access the full text report, will be excluded. The study population will include interventions featuring any kind of CA, including a text-based, voice-based, or embodied CA. Embodied CAs are defined as conversational interfaces that include a human-like avatar mimicking human movements and facial expressions. The eligible interventions will include any health care intervention focused on behavior change. This includes interventions focusing on improving or promoting a healthy lifestyle (eg, increase physical activity, weight loss, healthy eating) or managing physical or mental health disorders (eg, depression, diabetes, asthma, hypertension). These interventions should include a clear reference to behavior change as an essential aspect of the intervention, with or without reference to an associated behavioral change theory.

A data extraction form will be developed by the research team, which will include the following items: first author, year of publication, source of literature, title of article, study design and methods, geographic focus, health care sector, CA name, accessibility of CA, dialogue technique, input and output modalities, nature of the CA’s end goal, behavioral change theories or frameworks guiding the intervention, and BCTs used, mapped according to BCTTv1 [16].

Data from included studies will be extracted into a Microsoft Excel spreadsheet. Before starting the data extraction process, the table will be piloted by all members of the research team involved in this step, and amendments to the table will be made according to researchers’ feedback.

Data extraction for each paper will be performed by two researchers working independently, and the results will subsequently be compared. If disagreements arise, these will be resolved through consensus or consultation with a third reviewer acting as an arbiter.

Data will be tabulated and analyzed using descriptive statistics.

The data extracted from the included papers will be presented in a diagrammatic or tabular form accompanied by a narrative summary. We will provide an overview of the choice of BCTs in the included studies, the use of BCTs across different types of CAs and health care areas, the BCTs employed in the interventions that have been shown to be effective, and the theories or frameworks used in the development of behavior change interventions. We will also discuss any gaps in the evidence and provide recommendations for future use of BCTs in CA-delivered interventions.

We will also undertake a stakeholder consultation to inform the analysis and presentation of our findings. Stakeholders will include researchers in the field of CAs in health care. We will organize a seminar with the stakeholders, present our findings, and invite comments from the attendants. We will use the collated feedback to guide our analysis and reporting in our manuscript.

Ethical approval is not required for this study. We will disseminate our findings via a publication in a peer-reviewed journal and presentations at conferences.