  Prior HCI studies often analyzed smartphone app usage data for usability and
user experience research purposes. App usage videos are often collected by a
screen recording app in order to better analyze the app usage behaviors (e.g.,
app usage time, screen transition, and notification handling). However, it is
difficult to analyze app usage videos along with multiple user interaction
stream data. When the length of a video is long, data analysis tends to take a
long time due to the volume of user interaction data. This is even more
difficult for novice researchers due to a lack of data analysis experience. In
this paper, we propose LV-Linker (Log and Video Linker), a visualization tool
that helps researchers quickly explore the app usage log and video data by
linking multiple time series log data with the video data. We conducted a
preliminary user study with eight participants to evaluate the benefits of
linking, by measuring task completion time, helpfulness, and subjective task
workload. Our results showed that offering a linking feature significantly
lowers the task completion time and task workload.
