Usability of Interfaces
Mrio Simes-Marques, Isabel da Silva Lopes · InTech eBooks · 2012
In recent years human society evolved from the "industrial society age" and transitioned into the "knowledge society age".This means that knowledge media support migrated from "pen and paper" to computer-based Information Systems.This evolution introduced some technological, organizational, and methodological changes affecting the demand, workload and stress over the workers, many times in a negative way.Due to this fact Ergonomics assumed an increasing importance, as a science/technology that deals with the problem of adapting the work to the man, namely in terms of usability.Usability is a quality or characteristic of a product that denotes how easy this product is to learn and to use (Dillon, 2001); but it is also an ergonomic approach, and a group of principles and techniques aimed at designing usable and accessible products, based on usercentred design.User-centred design is a structured development methodology that focuses on the needs and characteristics of users, and should be applied from the beginning of the development process in order to make software applications more useful and easy to use (Averboukh, 2001;Nunes, 2006).Formally, usability is defined as "the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use" (ISO 9241 -Part 11) (ISO 9241, 1998).Therefore usability is a relative concept, which is dependent on several factors.It applies equally both to hardware and software design.Adequate usability is important because it is a characteristic of product quality that leads to improving product acceptability, increasing user satisfaction, improving product reliability and it is also financially beneficial to companies.Such benefit can be seen from two points of view, one related with workers' productivity (less training time and faster task completion), and the other with product sells (products are easier to sell and market themselves, when users had positive experiences) (Nunes, 2006).A product designed with the user psychological and physiological characteristics in mind, is more efficient to use (less time to accomplish a particular task), easier to learn (operations can be learned by observing the object), and more satisfying to use (Nielsen, 1993). www.intechopen.comErgonomics -A Systems Approach 156 Usability covers a broad spectrum of aspects regarding a product.Goud (Gould, 1995) argues that, despite several of these aspects are least discussed in literature, usability of components include components as System performance, System functions, User interface, Reading materials, Language translation, Outreach program, Ability for costumers to modify and extend, Installation, Field maintenance and serviceability, Advertising or Support-group users.However, some authors see this broad spectrum of issues as a step beyond usability, which is designated as User Experience Design.This theme is addressed in another chapter of the present book.The present chapter addresses usability in a traditional way, the one that relates mainly with the usability of interfaces, including aspects of system performance and system functions.