A Portable E-diary System for Assessing Physical Activity and Travel

Faculty: Weimo Zhu, Mark Hasegawa-Johnson

Students: Arthur Kantor

Sponsor: Active Living Research, the Robert Wood Johnson Foundation

Performance Dates:2002-2003

Written diaries have been widely used in self-report surveys to collect physical activity, travel behavior and time-use data. While diaries can provide detailed information on patterns of human behavior, they suffer from several limitations: (a) Scoring such diaries is a very labor-intensive activity and, as such, is very expensive; (b) Raters' objectivity is sometimes a concern when raters are not carefully trained, and (c) The diary may create a considerable burden on respondents when they are asked to record their activities several times a day and keep the records. In addition, no effort has been to develop and validate a diary that can measure both physical activity and travel behaviors.

The objectives of this study are to overcome the above limitations of diaries by developing an E-diary system, which combines voice-recognition and automatic scoring, and validate it using Armbend and GeoLoggers, two criterion measures based on advanced wireless and GPS technologies.

There were two stages in this project: Development and Validation. The purpose of the development stage was to develop an E-diary system. The first task in this stage was to develop an E-diary system and the second was to integrate MET scores with the system using the compendium of physical activities (Ainsworth et al., 2000) so that physical activities recorded could be scored. The purpose of the validation stage was to validate the E-diary system developed. For reliability, a total of 30 participants were recruited and they were asked to collect their physical activity diary data using the E-diary system for 21 consecutive days. Reliability coefficients were computed using the generalizability theory. For validity, those who participated in the reliability study were also asked to participate in the validity study, in which they were asked to record their physical and travel activities by the E-diary system, as well as wearing an Armbend and GeoLoggers, for seven days. The validity coefficients were computed by correlating the information recorded by the E-diary and those collected by the Armbend and GeoLoggers. Finally, for objectivity, expert judges were asked to rate 50 physical-activity and travel diaries randomly selected from the diaries collected. Kappa coefficients were computed to determine inter-rater objectivity using the data collected, i.e., classified physical activities. The agreements among the parties, including the E-diary system, Armband, and expert judges were computed using the kappa coefficients.