title: Analyzing engagement in a web-based intervention platform through visualizing log-data.
abstract: BACKGROUND
  Engagement has emerged as a significant cross-cutting concern within the development of Web-based interventions. There have been calls to institute a more rigorous approach to the design of Web-based interventions, to increase both the quantity and quality of engagement. One approach would be to use log-data to better understand the process of engagement and patterns of use. However, an important challenge lies in organizing log-data for productive analysis.
  
  
  OBJECTIVE
  Our aim was to conduct an initial exploration of the use of visualizations of log-data to enhance understanding of engagement with Web-based interventions.
  
  
  METHODS
  We applied exploratory sequential data analysis to highlight sequential aspects of the log data, such as time or module number, to provide insights into engagement. After applying a number of processing steps, a range of visualizations were generated from the log-data. We then examined the usefulness of these visualizations for understanding the engagement of individual users and the engagement of cohorts of users. The visualizations created are illustrated with two datasets drawn from studies using the SilverCloud Platform: (1) a small, detailed dataset with interviews (n=19) and (2) a large dataset (n=326) with 44,838 logged events.
  
  
  RESULTS
  We present four exploratory visualizations of user engagement with a Web-based intervention, including Navigation Graph, Stripe Graph, Start-Finish Graph, and Next Action Heat Map. The first represents individual usage and the last three, specific aspects of cohort usage. We provide examples of each with a discussion of salient features.
  
  
  CONCLUSIONS
  Log-data analysis through data visualization is an alternative way of exploring user engagement with Web-based interventions, which can yield different insights than more commonly used summative measures. We describe how understanding the process of engagement through visualizations can support the development and evaluation of Web-based interventions. Specifically, we show how visualizations can (1) allow inspection of content or feature usage in a temporal relationship to the overall program at different levels of granularity, (2) detect different patterns of use to consider personalization in the design process, (3) detect usability issues, (4) enable exploratory analysis to support the design of statistical queries to summarize the data, (5) provide new opportunities for real-time evaluation, and (6) examine assumptions about interactivity that underlie many summative measures in this field.
authors.affiliation: Engineering Design Centre, University of Cambridge, Cambridge, United Kingdom. cpm38@cam.ac.uk.
authors.forename: Cecily
authors.identifier: http://orcid.org/0000-0001-5013-3715
authors.initials: C
authors.lastname: Morrison
authors.forename: Gavin
authors.identifier: http://orcid.org/0000-0002-9617-7008
authors.initials: G
authors.lastname: Doherty
mesh_terms: D003196:Computer Graphics; D003661:Decision Support Techniques; D006801:Humans; D020407:Internet; D010346:Patient Care Management; D013812:Therapeutics
keywords: Web-based interventions; data visualisation; engagement; log-data analysis