Cost/benefit analysis for incorporating human factors in the software lifecycle
TL;DR: In this paper, the authors present methods for improvement of the user interface design, an overview of the human factors element, and cost/benefit aspects of user interfaces in interactive software environments.
Abstract: New software engineering techniques and the necessity to improve the user interface in increasingly interactive software environments have led to a change in traditional software development methods. Methodologies for improvement of the interface design, an overview of the human factors element, and cost/benefit aspects are explored.
Citations
More filters
TL;DR: In this article, the authors developed and validated new scales for two specific variables, perceived usefulness and perceived ease of use, which are hypothesized to be fundamental determinants of user acceptance.
Abstract: 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.
40,720 citations
Book•
01 Jan 1993
TL;DR: This guide to the methods of usability engineering provides cost-effective methods that will help developers improve their user interfaces immediately and shows you how to avoid the four most frequently listed reasons for delay in software projects.
Abstract: 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.
11,929 citations
01 May 1993
TL;DR: It is found that the detection of usability problems as a function of number of users tested or heuristic evaluators employed is well modeled as a Poisson process, which can be used to plan the amount of evaluation required to achieve desired levels of thoroughness or benefits.
Abstract: For 11 studies, we find that the detection of usability problems as a function of number of users tested or heuristic evaluators employed is well modeled as a Poisson process. The model can be used to plan the amount of evaluation required to achieve desired levels of thoroughness or benefits. Results of early tests can provide estimates of the number of problems left to be found and the number of additional evaluations needed to find a given fraction. With quantitative evaluation costs and detection values, the model can estimate the numbers of evaluations at which optimal cost/benefit ratios are obtained and at which marginal utility vanishes. For a “medium” example, we estimate that 16 evaluations would be worth their cost, with maximum benefit/cost ratio at four.
1,715 citations
Book•
20 Oct 2001
TL;DR: Usability Engineering: Scenario-Based Development of Human-Computer Interaction as discussed by the authors focuses on the realities of product development, showing how user interaction scenarios can make usability practices an integral part of interactive system development.
Abstract: Usability Engineering: Scenario-Based Development of Human-Computer Interaction is a radical departure from traditional books that emphasize theory and address experts. This book focuses on the realities of product development, showing how user interaction scenarios can make usability practices an integral part of interactive system development. As you'll learn, usability engineering is not the application of inflexible rules; it's a process of analysis, prototyping, and problem solving in which you evaluate tradeoffs, make reasoned decisions, and maximize the overall value of your product.
1,170 citations
TL;DR: This study clarifies the nature of user involvement and its expected benefits, and reviews three streams of research, to evaluate the benefits and problems of varied user involvement approaches in practice.
Abstract: User involvement is a widely accepted principle in development of usable systems. However, it is a vague concept covering many approaches. This study first clarifies the nature of user involvement and its expected benefits, and secondly reviews three streams of research, to evaluate the benefits and problems of varied user involvement approaches in practice. The particular focus of this study is on the early activities in the development process. An analysis of the literature suggests that user involvement has generally positive effects, especially on user satisfaction, and some evidence exists to suggest that taking users as a primary information source is an effective means of requirements capture. However, the role of users must be carefully considered and more cost-efficient practices are needed for gathering users' implicit needs and requirements in real product development contexts.
826 citations
References
More filters
Dissertation•
01 Jan 1985
5,244 citations
TL;DR: In this paper, the authors discuss modularization as a mechanism for improving the flexibility and comprehensibility of a system while allowing the shortening of its development time, and the effectiveness of modularization is dependent upon the criteria used in dividing the system into modules.
Abstract: This paper discusses modularization as a mechanism for improving the flexibility and comprehensibility of a system while allowing the shortening of its development time. The effectiveness of a “modularization” is dependent upon the criteria used in dividing the system into modules. A system design problem is presented and both a conventional and unconventional decomposition are described. It is shown that the unconventional decompositions have distinct advantages for the goals outlined. The criteria used in arriving at the decompositions are discussed. The unconventional decomposition, if implemented with the conventional assumption that a module consists of one or more subroutines, will be less efficient in most cases. An alternative approach to implementation which does not have this effect is sketched.
5,028 citations
Book•
01 Jan 1981
TL;DR: In this article, the authors provide an overview of economic analysis techniques and their applicability to software engineering and management, including the major estimation techniques available, the state of the art in algorithmic cost models, and the outstanding research issues in software cost estimation.
Abstract: This paper summarizes the current state of the art and recent trends in software engineering economics. It provides an overview of economic analysis techniques and their applicability to software engineering and management. It surveys the field of software cost estimation, including the major estimation techniques available, the state of the art in algorithmic cost models, and the outstanding research issues in software cost estimation.
4,440 citations
Book•
01 Jan 1986
TL;DR: A.A. Norman, Cognitive Engineering, Psychological Issues in Support of Multiple Activities, and D.W. diSessa, Notes on the Future of Programming: Breaking the Utility Barrier.
Abstract: Contents: S.W. Draper, D.A. Norman, C. Lewis, Introduction. Part I:User Centered System Design. K. Hooper, Architectural Design: An Analogy. L.J. Bannon, Issues in Design: Some Notes. D.A. Norman, Cognitive Engineering. Part II:The Interface Experience. B.K. Laurel, Interface as Mimesis. E.L. Hutchins, J.D. Hollan, D.A. NormanDirect Manipulation Interfaces. A.A. diSessa, Notes on the Future of Programming: Breaking the Utility Barrier. Part III:Users' Understandings. M.S. Riley, User Understanding. C. Lewis, Understanding What's Happening in System Interactions. D. Owen, Naive Theories of Computation. A.A. diSessa, Models of Computation. W. Mark, Knowledge-Based Interface Design. Part IV:User Activities. A. Cypher, The Structure of Users' Activities. Y. Miyata, D.A. Norman, Psychological Issues in Support of Multiple Activities. R. Reichman, Communication Paradigms for a Window System. Part V:Toward a Pragmatics of Human-Machine Communication. W. Buxton, There's More to Interaction Than Meets the Eye: Some Issues in Manual Input. S.W. Draper, Display Managers as the Basis for User-Machine Communication. Part VI:Information Flow. D. Owen, Answers First, Then Questions. C.E. O'Malley, Helping Users Help Themselves. L.J. Bannon, Helping Users Help Each Other. C. Lewis, D.A. Norman, Designing for Error. L.J. Bannon, Computer-Mediated Communication. Part VII:The Context of Computing. J.S. Brown, From Cognitive to Social Ergonomics and Beyond.
2,204 citations
Book•
01 Jan 1978
TL;DR: DeMarco's "Structured Analysis and System Specification" as mentioned in this paper is the final paper chosen for inclusion in this book of classic articles on the structured revolution, and it is a good summary of the current state of the art in structured analysis.
Abstract: DeMarco's "Structured Analysis and System Specification" is the final paper chosen for inclusion in this book of classic articles on the structured revolution. It is last of three on the subject of analysis, and, together with Ross/Schoman [Paper 22] and Teichroew/Hershey [Paper 23], provides a good idea of the direction that structured analysis will be taking in the next few years.
Any competent systems analyst undoubtedly could produce a five-page essay on "What's Wrong with Conventional Analysis." DeMarco, being an ex-analyst, does so with pithy remarks, describing conventional analysis as follows"
"Instead of a meaningful interaction between analyst and user, there is often a period of fencing followed by the two parties' studiously ignoring each other... The cost-benefit study is performed backwards by deriving the development budget as a function of expected savings. (Expected savings were calculated by prorating cost reduction targets handed down from On High.)"
In addition to providing refreshing prose, DeMarco's approach differs somewhat --- in terms of emphasis --- from that of Teichroew/Hershey and of Ross/Schoman. Unlike his colleagues, DeMarco stresses the importance of the maintainability of the specification. Take, for instance, the case of one system consisting of six million lines of COBOL and written over a period of ten years by employees no longer with the organization. Today, nobody knows what the system does.t Not only have the program listings and source code been lost --- a relatively minor disaster that we all have seen too often --- but the specifications are completely out of date. Moreover, the system has grown so large that neither the users nor the data processing people have the faintest idea of what the system is supposed to be doing, let alone how the mysterious job is being accomplished! The example is far from hypothetical, for this is the fate that all large systems eventually will suffer, unless steps are taken to keep the specifications both current and understandable across generations of users.
The approach that DeMarco suggests --- an approach generally known today as structured analysis --- is similar in form to that proposed by Ross and Schoman, and emphasizes a top-down, partitioned, graphic model of the system-to-be. However, in contrast to Ross and Schoman, DeMarco also stresses the important role of a data dictionary and the role of scaled-down specifications, or minispecs, to be written in a rigorous subset of the English language known as Structured English.
DeMarco also explains carefully how the analyst proceeds lrom a physical description of the user's current system, through a logical description of that same system, and eventually into a logical description of the new system that the user wants. Interestingly, DeMarco uses top-down, partitioned dataflow diagrams to illustrate this part of the so-called Project Life Cycle --- thus confirming that such a graphic model can be used to portray virtually any system.
As in other short papers on the subject, the details necessary for carrying out DeMarco's approach are missing or are dealt with in a superficial manner. Fortunately, the details can be found: Listed at the end of the paper are references to three full-length books and one videotape training course, all dealing with the kind of analysis approach recommended by DeMarco.
1,655 citations