Empirical comparison of task completion time between mobile phone models with matched interaction sequences


Event HCI International 2009


Victoria Bellotti
Nicholas Yee
Technical Publications
July 19th 2009
CogTool is a predictive evaluation tool for user interfaces. We wanted to apply CogTool to an evaluation of two mobile phones, but, at the time of writing, CogTool lacks the necessary (modeling baseline) observed human performance data to allow it to make accurate predictions about mobile phone use. To address this problem, we needed to collect performance data from both novice users and expert users interactions to plug into CogTool. Whilst novice users for a phone are easy to recruit, in order to obtain observed data on expert users performance, we had to recruit owners of our two target mobile phone models as participants. Unfortunately, it proved to be hard to find enough owners of each target phone model. Therefore we asked if multiple similar models that had matched interaction sequences could be treated as the same model from the point of view of expert performance characteristics. In this paper, we report an empirical experimental exercise to answer this question. We compared identical target task completion time for experts across two groups of similar models. Because we found significant differences in some of the task completion times within one group of models, we would argue that it is not generally advisable to consider multiple phone models as equivalent for the purpose of obtaining observed data for predictive modeling.


Suzuki, S.; Nakao, Y.; Asahi, T.; Bellotti, V.; Yee, N.; Fukuzumi, S. Empirical comparison of task completion time between mobile phone models with matched interaction sequences. Proceedings of HCI International 2009.; 2009 July 19-24; San Diego CA. Berlin: Springer; 2009; LNCS 5612: 114-122.

Additional information

Focus Areas

Our work is centered around a series of Focus Areas that we believe are the future of science and technology.

Licensing & Commercialization Opportunities

We’re continually developing new technologies, many of which are available for¬†Commercialization.


PARC scientists and staffers are active members and contributors to the science and technology communities.