Chad C. Tossell

LiveLab: measuring wireless networks and smartphone users in the field

We present LiveLab, a methodology to measure real-world smartphone usage and wireless networks with a reprogrammable indevice logger designed for long-term user studies. We discuss the challenges of privacy protection and power impact in LiveLab and offer our solutions. We present an iPhone 3GS based deployment of LiveLab with 25 users intended for one year. Early results from the data collection so far highlight the unique strengths and potential of LiveLab. We have two objectives in this position paper. First, we demonstrate the feasibility and capability of LiveLab. By sharing our experience, we seek to advocate LiveLab as a network and user measurement methodology. Second, we present our preliminary findings, and seek feedback from the community regarding what data to collect.

Characterizing web use on smartphones

The current paper establishes empirical patterns associated with mobile internet use on smartphones and explores user differences in these behaviors. We apply a naturalistic and longitudinal logs-based approach to collect real usage data from 24 iPhone users in the wild. These data are used to describe smartphone usage and analyze revisitation patterns of web browsers, native applications, and physical locations where phones are used. Among our findings are that web page revisitation through browsers occurred very infrequently (approximately 25% of URLs are revisited by each user), bookmarks were used sparingly, physical traversing patterns mirrored virtual (internet) traversing patterns and users systematically differed in their web use. We characterize these differences and suggest ways to support users with enhanced design of smartphone technologies and content.

Exploring iPhone usage: the influence of socioeconomic differences on smartphone adoption, usage and usability

Previous studies have found that smartphone users differ by orders of magnitude. We explore this variability to understand how users install and use native applications in ecologically-valid environments. A quasi-experimental approach is applied to compare how users in different socio-economic status (SES) groups adopt new smartphone technology along with how applications are installed and used. We present a longitudinal study of 34 iPhone 3GS users. 24 of these participants were chosen from two carefully selected SES groups who were otherwise similar and balanced. Usage data collected through an in-device programmable logger, as well as several structured interviews, identify similarities, differences, and trends, and highlight systematic differences in smartphone usage. A group of 10 lower SES participants were later recruited and confirm the influence of SES diversity on device usage. Among our findings are that a large number of applications were uninstalled, lower SES groups spent more money on applications and installed more applications overall, and the lowest SES group perceived the usability of their iPhones poorly in comparison to the other groups. We further discuss the primary reasons behind this low score, and suggest design implications to better support users across SES brackets.

An empirical analysis of smartphone personalisation: measurement and user variability

The present report is an empirical analysis of smartphone personalisation. We collected data from two groups of users to measure how they adapt the content, interface and physical appearance of their devices. This user-driven personalisation is measured with a simple heuristic approach to quantify the behaviour. Using these scores, we explore how users differ from each other in how they personalise their smartphones with a focus on gender differences, usability and device usage in the wild. Among our findings are that not all users personalise their smartphones, females and males personalise their iPhones differently, and those who personalised their phones more tended to rate it as more usable. The users who personalised more also used their device for greater periods of time on a broader range of applications. For instance, individuals who adapted their iPhones to a greater degree also accessed the Web more often and spent more time browsing once it was accessed. We conclude with a discussion of possible factors underlying the large user diversity of smartphone personalisation found in this research.

Practical Context Awareness: Measuring and Utilizing the Context Dependency of Mobile Usage

Context information brings new opportunities for efficient and effective applications and services on mobile devices. A wide range of research has exploited context dependency, i.e. the relations between context(s) and the outcome, to achieve significant, quantified, performance gains for a variety of applications and services. These works typically have to deal with the challenges of multiple context sources leading to a sparse training dataset, and the challenges of energy hungry context sensors. Often, they address these challenges in an application specific and ad-hoc manner. We liberate mobile application designers and researchers from these burdens by providing a methodical approach to these challenges. In particular, we 1) define and measure the context-dependency of three principal types of mobile usage (visited websites, phone calls, and app usage) in an application agnostic yet practical manner, providing insight into the performance of potential application. 2) Address the challenge of data sparseness when dealing with multiple context sources in a systematic manner. 3) Present SmartContext to address the energy challenge by automatically selecting among context sources while ensuring a minimum accuracy for each estimation. Our analysis and findings are based on one year of usage and context traces collected in real-life settings from 24 iPhone users. We present findings regarding the context dependency of three types of mobile usage from 24 users, yet our methodology and the lessons we learn can be readily extended to other types of usage as well as system resources. Our findings guide the development of context aware systems, and highlight the challenges and expectations regarding the context dependency of mobile usage.

Getting real: a naturalistic methodology for using smartphones to collect mediated communications

This paper contributes an intentionally naturalistic methodology using smartphone logging technology to study communications in the wild. Smartphone logging can provide tremendous access to communications data from real environments. However, researchers must consider how it is employed to preserve naturalistic behaviors. Nine considerations are presented to this end. We also provide a description of a naturalistic logging approach that has been applied successfully to collecting mediated communications from iPhones. The methodology was designed to intentionally decrease reactivity and resulted in data that were more accurate than self-reports. Example analyses are also provided to show how data collected can be analyzed to establish empirical patterns and identify user differences. Smartphone logging technologies offer flexible capabilities to enhance access to real communications data, but methodologies employing these techniques must be designed appropriately to avoid provoking naturally occurring behaviors. Functionally, this methodology can be applied to establish empirical patterns and test specific hypotheses within the field of HCI research. Topically, this methodology can be applied to domains interested in understanding mediated communications such as mobile content and systems design, teamwork, and social networks.

Voting on a Smartphone Evaluating the Usability of an Optimized Voting System for Handheld Mobile Devices

The goal of this research was to assess the usability of a voting system designed for current-generation smartphones. Smartphones offer remote participation in elections through the use of pervasive technology and voting on these devices could, among other benefits, increase voter participation while allowing voters to use familiar technology. We developed a mobile voting system for the iPhone and compared its usability with traditional voting platforms. Results showed that the mobile voting system was not as efficient as the other voting methods in total interaction time. However, smartphone owners committed fewer errors on the mobile voting system than on the traditional voting systems. These results, along with others, are discussed along with several important design considerations for voting technology.

Assessing the Performance of Common Tasks on Handheld Mobile Computers

The goal of this study was to examine three interfaces for handheld mobile computing (HMC) on the iPhone and then assess against a standard personal computer (PC) interface. While designers originally envisioned similar performance between HMC and PC, our results indicate differences between these platforms. However, specialized mobile sites and applications (Apps) greatly enhanced HMC performance on the iPhone. In particular, mobile content that required larger amounts of data entry benefited much more from these sorts of interfaces than mobile content for data acquisition.

Toward More Usable Electronic Voting Testing the Usability of a Smartphone Voting System

Objective: The goal of this research was to assess the usability of a voting system designed for smartphones. Background: Smartphones offer remote participation in elections through the use of pervasive technology. Voting on these devices could, among other benefits, increase voter participation while allowing voters to use familiar technology. However, the usability of these systems has not been assessed. Method: A mobile voting system optimized for use on a smartphone was designed and tested against traditional voting platforms for usability. Results: There were no reliable differences between the smartphone-based system and other voting methods in efficiency and perceived usability. More important, though, smartphone owners committed fewer errors on the mobile voting system than on the traditional voting systems. Conclusion: Even with the known limitations of small mobile platforms in both displays and controls, a carefully designed system can provide a usable voting method. Much of the concern about mobile voting is in the area of security; therefore, although these results are promising, security concerns and usability issues arising from mitigating them must be strongly considered. Application: The results of this experiment may help to inform current and future election and public policy officials about the benefits of allowing voters to vote with familiar hardware.

Effects of Socioeconomic diversity on iPod Touch Device Use in Real-World Environments

The iPod Touch provides portable and personalized information, entertainment, and communication resources for users. The goal of this study was to assess the influence of user diversity on how these handheld mobile computers are employed in real environments. Using an unobtrusive, longitudinal methodology to collect data, we explored how different socioeconomic groups personalize and operate iPod Touches. The lower income group used the instrumented iPod Touch more often and for different purposes. Design implications for newer-generation handheld devices and content are discussed.