- Email: [email protected]
Evaluating usability of human-computer interfaces: a practical method
Books Evaluation and design of human-computer interfaces for practitioners Evaluating usability computer interfaces." method
of humana practical
S Ravden and G Johnson John Wiley, Chichester, UK (1989) 126 pp £21.00 hardback
The usability of a computer system determines how effectively a user can employ the system to carry out required tasks. As the user can only use the system through interacting with its interface, the interface has to be usable to allow the whole system to be usable. This book presents a simple and practical method to evaluate how good the interface of a prototype or developed computer system is. The method described in this book is the result of two Esprit (European Strategic Programme for Research and Development in Information Technology) projects. It consists of an evaluation checklist presenting a structured set of interface guidelines and a procedure to use the checklist
to evaluate a user interface. The book is divided into three parts. The first part describes the ideas behind the method and provides a summary of its key features. The second describes the full evaluation checklist with accompanying instructions for its completion. The detailed explanations of design criteria and the guidelines behind the checklist are presented. The last part describes how to use the method in an evaluation. It discusses how to construct tasks for the evaluation, how to conduct the evaluation, and how to analyse the results of the evaluation. A nice aspect of this book is that it presents three case studies in its appendix. These case studies illustrate the application of the method in different situations. The method advocated in this book is not a panacea. It does not tell a designer how to solve interface design problems nor does it yield quantitative assessments of usability.
However, it does provide a method for identifying difficulties and weak areas of a computer interface that can be targeted for improvement. The book's organization of theoretical descriptions followed by practical examples is attractive and a practitioner can use this method to conduct an evaluation by reading this book. The checklist is mainly used for evaluation purposes. It also directs a HCI designer's attention to the aspects of an interface to which particular attention should be paid. The price of £21 for this book is a little bit high. Nevertheless, it is a practical book. It is generally recommended to practitioners and researchers who evaluate and design human-computer interfaces. It is specially recommended to people who design questionnaires for HCI evaluation. Y YANG Rutherford Appleton Laboratory Didcot, U K
Stimulating discussion on implementing data structures Reusable data structures for C R Sessions Prentice Hall, Englewood Cliffs, N J, USA (1989) 166 pp £27.80 softback
While this book does indeed show how certain data structures can be implemented reusably in c, it is not primarily a cook-book of data structures for copying into the reader's own programs. Instead, it shows how to write functions that implement a data structure in a way that allows them to be used, without modification, in a range of programs. Using the features of c that allow separate compilation, the details of the datastructure implementation are kept hidden from the program that uses them, and the details of their use are kept hidden
vol 32 no 7 september 1990
from the implementor of the linked list functions. Programmers familiar with languages like ADA will recognise that the author is providing the techniques for building generic packages in c. The book is aimed at professional c programmers, but it assumes little background in data structures. It emphasizes good programming practice throughout and includes a brief overview of step-wise refinement as a way of encouraging clean modularity and keeping the lowerlevel code as general as possible. The author's basic thesis is that reusability can be obtained by separating a problem into those parts that are specific to the current problem and those parts that are instances of a more general problem: the general
problem is then solved first and the solution kept for later reuse. It would be naive to suggest that this is all there is to reusability, but it is a well established technique. The books starts with a discussion of program readability and design and then moves on to a single data structure: the linked list. Over the next few chapters the simple linked list is slowly and carefully transformed from an application form into a generic data structure, which can be used by a variety of programs, perhaps several times in a program. The author includes examples of its use at each stage. Then comes a balanced discussion of the efficiency issues involved in this programming style, as well as techniques for speeding it up in criti-
509
of humana practical
S Ravden and G Johnson John Wiley, Chichester, UK (1989) 126 pp £21.00 hardback
The usability of a computer system determines how effectively a user can employ the system to carry out required tasks. As the user can only use the system through interacting with its interface, the interface has to be usable to allow the whole system to be usable. This book presents a simple and practical method to evaluate how good the interface of a prototype or developed computer system is. The method described in this book is the result of two Esprit (European Strategic Programme for Research and Development in Information Technology) projects. It consists of an evaluation checklist presenting a structured set of interface guidelines and a procedure to use the checklist
to evaluate a user interface. The book is divided into three parts. The first part describes the ideas behind the method and provides a summary of its key features. The second describes the full evaluation checklist with accompanying instructions for its completion. The detailed explanations of design criteria and the guidelines behind the checklist are presented. The last part describes how to use the method in an evaluation. It discusses how to construct tasks for the evaluation, how to conduct the evaluation, and how to analyse the results of the evaluation. A nice aspect of this book is that it presents three case studies in its appendix. These case studies illustrate the application of the method in different situations. The method advocated in this book is not a panacea. It does not tell a designer how to solve interface design problems nor does it yield quantitative assessments of usability.
However, it does provide a method for identifying difficulties and weak areas of a computer interface that can be targeted for improvement. The book's organization of theoretical descriptions followed by practical examples is attractive and a practitioner can use this method to conduct an evaluation by reading this book. The checklist is mainly used for evaluation purposes. It also directs a HCI designer's attention to the aspects of an interface to which particular attention should be paid. The price of £21 for this book is a little bit high. Nevertheless, it is a practical book. It is generally recommended to practitioners and researchers who evaluate and design human-computer interfaces. It is specially recommended to people who design questionnaires for HCI evaluation. Y YANG Rutherford Appleton Laboratory Didcot, U K
Stimulating discussion on implementing data structures Reusable data structures for C R Sessions Prentice Hall, Englewood Cliffs, N J, USA (1989) 166 pp £27.80 softback
While this book does indeed show how certain data structures can be implemented reusably in c, it is not primarily a cook-book of data structures for copying into the reader's own programs. Instead, it shows how to write functions that implement a data structure in a way that allows them to be used, without modification, in a range of programs. Using the features of c that allow separate compilation, the details of the datastructure implementation are kept hidden from the program that uses them, and the details of their use are kept hidden
vol 32 no 7 september 1990
from the implementor of the linked list functions. Programmers familiar with languages like ADA will recognise that the author is providing the techniques for building generic packages in c. The book is aimed at professional c programmers, but it assumes little background in data structures. It emphasizes good programming practice throughout and includes a brief overview of step-wise refinement as a way of encouraging clean modularity and keeping the lowerlevel code as general as possible. The author's basic thesis is that reusability can be obtained by separating a problem into those parts that are specific to the current problem and those parts that are instances of a more general problem: the general
problem is then solved first and the solution kept for later reuse. It would be naive to suggest that this is all there is to reusability, but it is a well established technique. The books starts with a discussion of program readability and design and then moves on to a single data structure: the linked list. Over the next few chapters the simple linked list is slowly and carefully transformed from an application form into a generic data structure, which can be used by a variety of programs, perhaps several times in a program. The author includes examples of its use at each stage. Then comes a balanced discussion of the efficiency issues involved in this programming style, as well as techniques for speeding it up in criti-
509