Introduction

Simply stated, the term ‘usability’ means how easily a product or a service can be used. In the context of digital libraries, usability studies involve both user studies and evaluation of digital library products and services. A number of models of usability have been proposed in the literature. However, usability studies originated in, and have been largely conducted in the context of, the field of human–computer interactions (HCI). Hearst (2009) comments that usability is an important quality of a user interface. Nielsen (2003, 2006) comments that usability depends on five qualities of the interface of an information service: learnability, efficiency, memorability, errors and satisfaction. These parameters focus on measuring the features of user interfaces and are built on the design guidelines of user interfaces proposed by Shneiderman and Plaisant (2010).

However, the usability of a digital library is not limited to its interface features; rather, it should focus on the overall digital library service. Kuniavsky (2003) suggests that there are four major steps in a usability study of information systems:

While these guidelines may be used for conducting usability studies of digital libraries, a number of challenges are involved here. This chapter addresses these issues and, drawing examples from several usability studies, it discusses different approaches and techniques for conducting usability studies of digital libraries. Some socio-economic issues affecting the usability of digital libraries, such as the digital divide and emerging business models, are also mentioned.

Usability

ISO 9241 Part 11 (1998) defines usability 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. This definition reminds us that the users should be able to use an information product or service with effectiveness, efficiency and satisfaction in a specified context of use.