Concertina browsers: a formative evaluation of user preference

Evidence suggests that concertina browsers - browsers with the facility to expand and contract sections of information - are important in providing the reader with an enhanced cognition of small to medium amounts of information. These systems have been shown to be useful for visually disabled users surfing the World Wide Web (Web), and with the development of the Mobile Web, there has been renewed interest in their use. This is due to the similarities of reduced or constrained vision found to exist between visually impaired users and the users of mobile devices. The cognition of information fragments is key to the user experience and the reduction of 'information overload'; as such we are concerned with assisting designers of concertina browsers in providing an enhanced user experience by ascertaining user preference through a formative evaluation of concertina summaries. This aspect of browsing is important because in all concertina systems there is a distinct cognition speed/depth trade-off. Here we investigate a number of these concertina summarization techniques against each other. We describe a formative evaluation which concludes that users prefer concertina summarization of Web documents starting from 6.25% slices of both the top and bottom and expanding from the top in 2% steps to a target maximum of 18.50% (being 12.25% from the top and 6.25% from the bottom). These preferences were found to be representative of documents of less than 600 words of content, and included the preference to not fragment an individual sentence even if that meant slightly increasing the target: Starting, maximum, and step percentage slices.