There’s No Such Thing as Gaining a Pound: Reconsidering the Bathroom Scale User Interface
Matthew Kay, Dan Morris, mc schraefel, Julie A. Kientz
ACM SIGCHI UbiComp 2013 | 
BEST PAPER AWARD
Results of the four Likert-scale questions on scale attitudes, broken down by the quality of the respondents’ estimation of within-day weight fluctuation and by whether or not respondents weighed themselves regularly.
Abstract
The weight scale is perhaps the most ubiquitous health sensor of all and is important to many health and lifestyle decisions, but its fundamental interface—a single numerical estimate of a person’s current weight—has remained largely unchanged for 100 years. An opportunity exists to impact public health by re-considering this pervasive interface. Toward that end, we investigated the correspondence between consumers’ perceptions of weight data and the realities of weight fluctuation. Through an analysis of online product reviews, a journaling study on weight fluctuations, expert interviews, and a large-scale survey of scale users, we found that consumers’ perception of weight scale behavior is often disconnected from scales’ capabilities and from clinical relevance, and that accurate understanding of weight fluctuation is associated with greater trust in the scale itself. We propose significant changes to how weight data should be presented and discuss broader implications for the design of other ubiquitous health sensing devices.