Multi-User Usability Guidelines for Interactive Wall Display Applications Andrea Nutsi, Michael Koch Bundeswehr University Munich Werner-Heisenberg-Weg 39, D-85577 Neubiberg {andrea.nutsi | michael.koch} @unibw.de ABSTRACT Large interactive wall displays for multi-user interaction are readily available today. However, little is known about the specific aspects influencing usability for applications support- ing several users interacting simultaneously and co-located with wall displays. Our research aims to name these aspects and develop a set of usability guidelines for this type of ap- plications. These guidelines should support designers and de- velopers in the design phase and ensure a high usability of the application. In order to archive this, we analyse literature and conduct usability studies. In this paper we present a first set of usability guidelines derived from literature focusing on as- pects specific to multi-user interaction. One example is to consider bystanders, offer those who are not directly interact- ing valuable information and ensure readability for them. Author Keywords multi-user; interactive wall display; usability; guidelines ACM Classification Keywords H.5.2. Information Interfaces and Presentation (e.g. HCI): Ergonomics, Style guides INTRODUCTION Today interactive displays are readily available due to tech- nological progress [14] and falling costs [3]. This enables the development of multi-user interfaces which are spreading in industry and research [18]. Several users may interact syn- chronously and co-located with an application running on a large multi-touch wall display. This poses several challenges for designers and developers of such applications, as the spe- cific characteristics of the setting differ largely from desk- top PCs [4]. Therefore, guidelines and standards for desktop applications cannot be directly applied to multi-touch appli- cations. Guidelines, standards and style guides are tools to ensure good usability of a system [16], but do not exist for applications running on large public displays [1] nor (to our knowledge) for the semi-public context. Which factors are Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for third-party components of this work must be honored. For all other uses, contact the Owner/Author. Copyright is held by the owner/author(s). PerDis ’15, June 10-12, 2015, Saarbruecken, Germany ACM 978-1-4503-3608-6/15/06. http://dx.doi.org/10.1145/2757710.2776798 influencing the usability of a multi-user application? With our research we aim to answer this question and develop us- ability guidelines for multi-user applications running on large interactive wall displays, focusing on a semi-public context. Our methodology for developing these guidelines is based on the research approach of Paddison & Englefield [11] who suggest two methods for developing usability heuristics: 1. research-based: analysing literature and deriving heuristics based on this analysis, and 2. evaluation-based: summing up evaluation results in order to derive heuristics. We combine the results of a literature analysis with usability studies focus- ing on aspects unique to multiple users interacting simultane- ously with the display. Identification of the aspects unique to multi-user interaction will be done in the literature study complemented by a multi-user usability study of our existing MeetingMirror application [5]. In this paper we present the intermediate result of the first step: a set of usability guide- lines derived from literature. RELATED WORK Somervell et al. [15] developed usability heuristics for large screen information exhibits. These heuristics mainly sup- port the evaluation of a system, while our research targets the design phase aiming at supporting the developers of this type of applications. Furthermore, this set of heuristics does not focus on multi-user and multi-touch aspects. The guide- lines for public displays developed by [1] are also targeted at the evaluation. Yuill & Rogers [18] list aspects relevant to the design and evaluation of collaborative multi-user appli- cations. This research focuses on archiving a good collabo- ration whereas we target usability. Furthermore, Microsoft published a guideline for developing applications for their Perceptive Pixel display [7]. Industrial guidelines are opti- mized and targeted for their specific product and cannot be easily applied to other systems and devices [4]. Furthermore, the guidelines lack in empirical evidence and their develop- ment is not transparent to the reader. FIRST RESULTS The analysis of relevant literature is ongoing, nevertheless we want to provide a first set of guidelines derived from this work: • Do not use audio as it might be distracting to others [15]. • Consider users not directly interacting with the screen, of- fer additional value to them [8].