Perceived Usefulness, Perceived Ease of Use, and User

Valid measurement scales for predicting user acceptance of computers are in short supply. Most subjective measures used in practice are unvalidated, and their relationship to system usage is unknown. The present research develops and validates new scales for two specific variables, perceived usefulness and perceived ease of use, which are hypothesized to be fundamental determinants of user acceptance. Definitions of these two variables were used to develop scale items that were pretested for content validity and then tested for reliability and construct validity in two studies involving a total of 152 users and four application programs. The measures were refined and streamlined, resulting in two six-item scales with reliabilities of .98 for usefulness and .94 for ease of use. The scales exhibited hgih convergent, discriminant, and factorial validity. Perceived usefulness was significnatly correlated with both self-reported current usage r = .63, Study 1) and self-predicted future usage r = .85, Study 2). Perceived ease of use was also significantly correlated with current usage r = .45, Study 1) and future usage r = .59, Study 2). In both studies, usefulness had a signficnatly greater correaltion with usage behavior than did ease of use. Regression analyses suggest that perceived ease of use may actually be a causal antecdent to perceived usefulness, as opposed to a parallel, direct determinant of system usage. Implications are drawn for future research on user acceptance.

Perceived usefulness, perceived ease of use, and user acceptance of information technology

Computer systems cannot improve organizational performance if they aren't used. Unfortunately, resistance to end-user systems by managers and professionals is a widespread problem. To better predict, explain, and increase user acceptance, we need to better understand why people accept or reject computers. This research addresses the ability to predict peoples' computer acceptance from a measure of their intentions, and the ability to explain their intentions in terms of their attitudes, subjective norms, perceived usefulness, perceived ease of use, and related variables. In a longitudinal study of 107 users, intentions to use a specific system, measured after a one-hour introduction to the system, were correlated 0.35 with system use 14 weeks later. The intention-usage correlation was 0.63 at the end of this time period. Perceived usefulness strongly influenced peoples' intentions, explaining more than half of the variance in intentions at the end of 14 weeks. Perceived ease of use had a small but significant effect on intentions as well, although this effect subsided over time. Attitudes only partially mediated the effects of these beliefs on intentions. Subjective norms had no effect on intentions. These results suggest the possibility of simple but powerful models of the determinants of user acceptance, with practical value for evaluating systems and guiding managerial interventions aimed at reducing the problem of underutilized computer technology.

User Acceptance of Computer Technology: A Comparison of Two Theoretical Models

From the Publisher:
Written by the author of the best-selling HyperText & HyperMedia, this book provides an excellent guide to the methods of usability engineering. Special features: emphasizes cost-effective methods that will help developers improve their user interfaces immediately, shows you how to avoid the four most frequently listed reasons for delay in software projects, provides step-by-step information about which methods to use at various stages during the development life cycle, and offers information on the unique issues relating to informational usability. You do not need to have previous knowledge of usability to implement the methods provided, yet all of the latest research is covered.

Usability Engineering

Attention and Effort

This article is both theoretical and empirical. Theoretically, it describes three principles of system design which we believe must be followed to produce a useful and easy to use computer system. These principles are: early and continual focus on users; empirical measurement of usage; and iterative design whereby the system (simulated, prototype, and real) is modified, tested, modified again, tested again, and the cycle is repeated again and again. This approach is contrasted to other principled design approaches, for example, get it right the first time, reliance on design guidelines. Empirically, the article presents data which show that our design principles are not always intuitive to designers; identifies the arguments which designers often offer for not using these principles—and answers them; and provides an example in which our principles have been used successfully.

Designing for usability: key principles and what designers think

Any system designed for people to use should be (a) easy to learn; (b) useful, i.e., contain functions people really need in their work; (c) easy to use; and (d) pleasant to use. In this note we present theoretical considerations and empirical data relevant to attaining these goals. First, we mention four principles for system design which we believe are necessary to attain these goals; Then we present survey results that demonstrate that our principles are not really all that obvious, but just seem obvious once presented. The responses of designers suggest they may sometimes think they are doing what we recommend when in fact they are not. This is consistent with the experience that systems designers do not often recommend or use them themselves. We contrast some of these responses with what we have in mind in order to provide a more useful description of our principles. Lastly, we consider why this might be so. These sections are summaries of those in a longer paper to appear elsewhere (Gould & Lewis, 1983). In that paper we elaborate on our four principles, showing how they form the basis for a general methodology of design, and we describe a successful example of using them in actual system design (IBM's Audio Distribution System).

Designing for usability—key principles and what designers think

Publisher Summary This chapter describes the way in which usable systems can be designed. Usability is a combination of many factors, each of which is often developed independently. User-interface code is becoming an increasingly large percentage of the total system code. Standards are beginning to emerge for user interface design. Establishing standards for software aspects of the user interface is probably premature. There are lots of guidelines for a good system design. However, these are not enough for the design of good systems. One should at the beginning and throughout development focus on prospective users and their work. It is often heard that people buy computer systems for the functions in them. One is unlikely to figure out what the functions should be without talking with users. One should continuously measure each aspect of usability, and then iterate in a hill-climbing way toward a better system. All aspects of usability should begin evolving from the beginning and should be under one focus.

How to design usable systems

Almost a decade has passed since we started advocating a process of usability design. This article is a status report about the value of this process and, mainly, a description of new ideas for enhancing the use of the process

Making usable, useful, productivity-enhancing computer applications

Experiments, including our own (Gould and Grischkowsky, 1984; Gould et al., 1987), have shown that people read more slowly from CRT displays than from paper. This series of six experiments shows wh...

John D. Gould

Papers

Designing for usability: key principles and what designers think

Designing for usability—key principles and what designers think

How to design usable systems

Making usable, useful, productivity-enhancing computer applications

Reading from CRT displays can be as fast as reading from paper