Discerning Actuality in Backstage - Comprehensible Contextual Aging

The digital backchannel Backstage aims at supporting active and socially enriched participation in large class lectures by improving the social awareness of both lecturer and students. For this purpose, Backstage provides microblog-based communication for fast information exchange among students as well as from audience to lecturer. Rating enables students to assess relevance of backchannel messages for the lecture. Upon rating a ranking of messages can be determined and immediately presented to the lecturer. However, relevance is of temporal nature. Thus, the relevance of a message should degrade over time, a process called aging. Several aging approaches can be found in the literature. Many of them, however, rely on the physical time which only plays a minor role in assessing relevance in lecture settings. Rather, the actuality of relevance should depend on the progress of a lecture and on backchannel activity. Besides, many approaches are quite difficult in terms of comprehensibility, interpretation and handling. In this article we propose an approach to aging that is easy to understand and to handle and therefore more appropriate in the setting considered.