Interactive Television Accessibility and Usability

Introduction

Today, there are more than 70 million people aged 60 and above in the European Union.

According to Eurostat, over the next 15 years, the population aged 65 and over will increase by 22%. Many of these citizens will experience dexterity, cognitive, hearing, and sight problems in later life. This means that more than one in seven adults in Europe will have hearing problems. Some 7.4 million people already suffering uncorrectable sight loss will add to the number of European citizens experiencing some form of sensory impairment (Stallard, 2003).

Interactive digital television (iTV) is evolving into an enhanced entertainment and information service. There are various degrees of interactivity in digital television: pressing a simple remote control button, sending information back and forth, or servicing providers by means of a return path. If they are to be adopted, interactive facilities need to be usable by viewers, even because, as Jacob Neilsen points out, “increased accessibility for users with disabilities almost invariably leads directly to improved usability for all users” (Slatin & Rush, 2003). Unfortunately, interactive digital television design appears to have been based on the conceptual models of keyboard-based systems, but their users, skills, goals and attitude of interaction differ. The TV audience is more diverse, some having no prior computer experience. It must be realised that iTV is not a PC and therefore cannot be treated as such.

As far as usabiltity for interactive television, a literature review shows that the approach followed by the majority of scientific publications is also mainly PC-centric and in the majority of cases implicitly focused on the work environment. Differences between the two environments and strategies for resolution of the issues involved have been noted by academics and practitioners (Chorianopoulos, 2003). Unfortunately, traditional usability engineering techniques focus on and have been developed to measure work-related goals like successful task completion, efficiency and error rate, parameters usually positively correlated with user satisfaction. 
In a usability test of three video interfaces, users preferred the interface that required more time, clicks, and had the highest error rate. According to Drucker, Glatzer, De Mar, and Wong (2002), ‘While the performance based on time to task completion and number of clicks was the worst in the novel interface, the user satisfaction was significantly better with this interface.’ Users made their choice on the basis of how amusing and relaxing an interface was.

The emergence of interactive television requires a fresh view of current paradigms. New usability evalutation techniques for interactive television must be designed and experimented with. This brings new challenges for television programme producers who have no strong tradition of minutely analysing viewer interaction with television, preferring instead to rely on survey methods such as diaries, questionnaires, focus groups, or automated monitoring to discover viewers’ attitudes (Gauntlett & Hill, 1999). Several evaluation techniques may be applicable to digital television, including analytical approaches such as heuristic evaluation (Nielsen, 1993), consisting of having a small set of evaluators examine the interface and judge its compliance with recognised usability principles («heuristics»). Building on growing evidence from studies reported in the literature, it is becoming possible to derive TV-specific heuristics. Nonetheless, nothing has yet been definitively established. Here we concentrate on empirical evaluation, based on observation and interview sessions with viewers. 

According to Pemberton and Griffiths (n.d.), there are a number of areas that distinguish the use of personal computers from the use of iTV. These differences suggest that evaluating digital television might require an approach differing from that for desktop applications. They also suggest that results reliable for desktop applications may need handling with more caution in an interactive television context. According to Gauntlett and Hill (1999) and Masthoff (2002), the major differences are: