Tse, T., Vegh, S., Marchionini, G., Shneiderman, B. (November 1999)
The purpose of this exploratory study is to develop research methods to compare the effectiveness of two video browsing interface designs, or surrogates—one static (storyboard) and one dynamic (slide show)—on two distinct information seeking tasks (gist determination and object recognition). Although video data is multimodal, potentially consisting of images, speech, sound, and text, the surrogates tested depend on image data only and use key frames or stills extracted from source video. A test system was developed to determine the effects of different key frame displays on user performance in specified information seeking tasks. The independent variables were interface display and task type. The dependent variables were task accuracy and subjective satisfaction. Covariates included spatial visual ability and time-to-completion. The study used a repeated block factorial 2x2 design; each of 20 participants interacted with all four interface-task combinations. No statistically significant results for task accuracy were found. Statistically significant differences were found, however, for user satisfaction with the display types: users assessed the static display to be "easier" to use than the dynamic display for both task types, even though there were no performance differences. This methodological approach provides a useful way to learn about the relationship between surrogate types and user tasks during video browsing.