Copyright 2006 John Wiley & Sons, Inc. Chapter 1 - Introduction

Copyright 2006 John Wiley & Sons, Inc. Introduction HCI: Human Computer Interaction Two organizing themes: multi-layer description of HCI and analysis of the cognitive and affective resources needed for user activities

Copyright 2006 John Wiley & Sons, Inc. HCI (Human Computer Interaction) HCI –is the set of processes and resources that users employ to interact with computers Building the human computer interface requires 50-70% of systems development effort To users, the interface is the system A study by Nielsen (2003) indicates that if corporations spend 10% of their development budget on usability, they can improve usability by 135%

Copyright 2006 John Wiley & Sons, Inc. Another study found that 51% of major websites violate the most basic design guidelines. These studies and more demonstrate that there is a need for a more systematic treatment of HCI in the development process and more HCI experts are needed. The Importance of HCI

Copyright 2006 John Wiley & Sons, Inc. When HCI fails, the system fails

Copyright 2006 John Wiley & Sons, Inc. Organizations of HCI are growing rapidly There are more new journals dedicated to HCI than any other information systems sub-discipline The Importance of HCI

Copyright 2006 John Wiley & Sons, Inc. What constitutes a good user interface? A good user interface:  Achieves required performance by operator, control, and maintenance personnel.  يحقق الأداء المطلوب: تحكم, صيانة  Minimizes skill and personnel requirements and training time  لا يطلب مهارات من المستخدم لاستعمال النظام أي أن المستخدم البسيط يمكنه التعامل مع النظام.  Fosters design standardization within and among systems  يعزز مقاييس التصميم في التظام.

Copyright 2006 John Wiley & Sons, Inc. Common measurable goals for usability  Time to learn how to operate the system  Speed of performance  Error rate What constitutes a good user interface?

Copyright 2006 John Wiley & Sons, Inc. How to achieve these goals? Achievement of these goals is no easy task Some goals may be conflicting (speed of performance and error rates). These two websites present similar functionality but have different designs. Assuming they are equally functional (easy to navigate and find products), which do you prefer? Why?

Copyright 2006 John Wiley & Sons, Inc. Site 1 has more text and less graphics

Copyright 2006 John Wiley & Sons, Inc. Site 2 is more graphic with less text Which is more important in this context?

Copyright 2006 John Wiley & Sons, Inc. Interdisciplinary nature and scope of HCI

Copyright 2006 John Wiley & Sons, Inc. Organizing theme One: Multi- layer model of HCI Fit: the match between the computer design and the user and task so as to minimize the user’s human resources needed to accomplish the task Figure 1.4 The Fit of HCI Components leads to Performance

Copyright 2006 John Wiley & Sons, Inc. Multi-layer model of HCI Figure 1.6 A Multi-layer model of HCI

Copyright 2006 John Wiley & Sons, Inc. Multi-layer model of HCI (TSSL) The task level pertains to the information requirements that have to be met. The semantic level pertains to the set of objects and operations through which the computer becomes meaningful to the user. The syntactic level dictates the rules of combining the semantic objects and operations into correct instructions. The lexical level describes the way specific computer devices are used to implement the syntactic level, e.g., move a mouse pointer to the document label and click twice to open it.

Copyright 2006 John Wiley & Sons, Inc. Organizing theme two: Human Resources in HCI and their impact Figure 1.7 The Relationship between User Activity and HCI supported resources

Copyright 2006 John Wiley & Sons, Inc. Context The general context of HCI is organizational work. For building an application, the context must be refined further at the specific task level. Summary  Our design philosophy is to develop the technology so as to achieve a good fit between the user, the task, and the technology, within a given context.

Copyright 2006 John Wiley & Sons, Inc. A Methodology for HCI Development The methodology revolves around a systems development life cycle that includes 4 phases: planning, analysis, design, and implementation/operation. Each phase focuses on 4 human concerns of HCI: Physical, cognitive, affective, and usefulness. Evaluation is also key and includes both formative (intermediary) and summative evaluation.

Copyright 2006 John Wiley & Sons, Inc. 4 phases of HCI development methodology The planning phase determines the organizational information needs. Analysis involves several unique HCI techniques. We believe that HCI considerations should start in the analysis stage to uncover user needs and opportunities. Three major analyses are conducted: context, user, and task analyses. The design phase specifies the user interface on the basis of the analysis according to HCI principles and guidelines and tested against the evaluation metrics. Finally, the implementation stage makes the target system a reality.

The HCI Methodology