Abstract: What is the Precursor in mHealth System Use? The Time Dynamics of Communicative Use on an mHealth Application

◆ Ellie F. Yang, University of Wisconsin-Madison
◆ Ran Z. Mi, University of Wisconsin-Madison
◆ Dhavan V. Shah, University of Wisconsin-Madison
◆ Dave Gustafson, University of Wisconsin-Madison

Background: One goal of mobile health (mHealth) systems is to facilitate interactive communication among users, healthcare providers and information sources (Fiordelli, Diviani, & Schulz, 2013). Understanding the use of mHealth communicative functions can provide insights to improve system quality and evaluation criteria (Kim, Ray & Veluscek, 2017; Chib & Lin, 2018). Many mHealth studies have focused on input factors such as accessibility or usability, and output factors such as process efficiencies for certain health outcomes (Chib & Lin, 2018), but few has investigated the interdependent relations between different uses of communicative functions (e.g., how earlier public posting behavior encourages later one-to-one messaging). We address this research gap using time series models to provide evidence that certain types of system uses can inspire subsequent system use, with the modes of interaction shifting with experience.

Objective: Our research examines different communicative sub-functions within a mobile health app developed to support addiction recovery and to see how they influence each other as time passes. Specifically, we investigated the interaction among two user activities (exposure vs. production) afforded by three distinct communicative functions (i.e., intrapersonal, dyadic, and public) for substance use disorders recovery. Six time series per user (N=255) were modeled to understand the interdependent dynamics.

Public (one to many communication) exposure. Browse/read a list of discussion groups/pages/posts in the discussion room.
Public production. Compose or edit a post in the discussion room.
Dyadic (one to one communication) exposure. Browse/read a list of messages sent from the other user or archived.
Dyadic production. Compose a message privately.
Intrapersonal exposure. Browse/read past self-writing motivation journal entries/photos.
Intrapersonal production. Compose a motivation journal only viewable to oneself.

Methods: We analyzed the number of clicks extracted from system log from 2014 to 2017. We categorized click counts based on (1) whether they were linked to exposure or production; and (2) which communicative function they reflect. Panel vector autoregression models (VARs) were adopted to capture the trends of interdependency and mutual influence in a time-series manner (Wells, et al., 2019; Box-Steffensmeier et al., 2015).

Results: Our data showed previous public exposure (with one-day lag) significantly boosted subsequent public production (β = .005, p <.05), dyadic production (β = .001, p <.05) and intrapersonal exposure (β = .003, p <.05). Previous intrapersonal production increased public exposure (β = 2.458, p <.05), suggesting a mutually reinforcing effect. Previous public production also improved dyadic production (β = .01, p <.05). In all, previous one-day exposure to public communicative functions could increase other types of mHealth use.

Conclusions: The study contributed to understanding relations among mHealth communicative functions through which users can be exposed to messages or produce content. Adherence to public communication, particular for exposure to discussion room contents, can boost other types of interaction in the system. Improving user engagement with public communicative functions is suggested to be a primary concern for mHealth design.