Sharon McDonald

People and computers XIV - Usability or else! : proceedings of HCI 2000

This text represents a comprehensive guide to research in HCI, and hopes to be essential reading for all researchers, designers and manufacturers who need to keep abreast of developments in HCI.

The repertory grid technique: Its place in empirical software engineering research

Personal construct theory (applied via the repertory grid technique) supports interpretivist research in a structured manner and, as such, has relevance for researchers conducting studies focused on the human and organisational aspects of software engineering. Personal construct theory (which underpins the repertory grid technique) is introduced, and the technique and its administration is discussed. Research studies from the literature are reviewed to provide illustrative examples of its application within a software engineering context. Since any research approach needs to answer questions about its reliability and validity within a particular study, these issues are considered for repertory grid investigations and criteria are offered that can be used to judge these issues within a planned, and/or reported, study.

Evaluating a content based image retrieval system

Content Based Image Retrieval (CBIR) presents special challenges in terms of how image data is indexed, accessed, and how end systems are evaluated. This paper discusses the design of a CBIR system that uses global colour as the primary indexing key, and a user centered evaluation of the systems visual search tools. The results indicate that users are able to make use of a range of visual search tools, and that different tools are used at different points in the search process. The results also show that the provision of a structured navigation and browsing tool can support image retrieval, particularly in situations in which the user does not have a target image in mind. The results are discussed in terms of their implications for the design of visual search tools, and their implications for the use of user-centered evaluation for CBIR systems.

Who should test whom

Examining the use and abuse of personality tests in software engineering.

Keep talking: an analysis of participant utterances gathered using two concurrent think-aloud methods

This paper presents the results of a study that compared two think-aloud styles: the classic approach and a relaxed think-aloud on the nature and number of participant utterances produced. Overall, ten categories of utterance were extracted from the verbal data ranging from categories that had a direct impact on usability problem analysis, to those which simply described procedural actions. There were no categories of utterance that were unique to either method. The interactive think-aloud led to the production of more utterances that could be directly used in usability problem analysis. Participants provided explanations, opinions and recommendations during classic think-aloud, even though they were not instructed to do so. This finding suggests that the social context of testing may override the classic instruction to think aloud.

The impact of two different think-aloud instructions in a usability test: a case of just following orders?

The instructions used in think-aloud studies can range from a simple request to think-aloud, to an explicit instruction to include certain types of content. The present study compared two think-aloud instructions: the classic neutral think-aloud instruction and an explicit instruction requesting explanations and content that is relevant to the user experience. Data from task performance, mental workload, think-aloud protocols and usability problems were collected from 16 participants, equally distributed between the two think-aloud instruction conditions. No differences were found in task performance, however, participants in the explicit instruction condition reported higher mental workload and a focus on finding interface problems. The explicit instruction condition also yielded more utterances about the user experience, expectations and explanations of behaviour than the neutral condition. An analysis of the resultant usability problems revealed that the explicit instruction led to a larger number of dialogue, navigation, layout and functionality problems, but that the problems which were unique to this condition were, in the main, at a low level of severity.

Modified contextual design as a field evaluation method

Downstream utility is a critical success factor for usability evaluation methods, in terms of the extent to which they can deliver value. In this paper we argue that field methods can significantly improve downstream utility through the added value they provide in terms of the range of usability problems they uncover and the contextual information they yield on user difficulties and their causal explanations. By way of an example we describe our experience of applying an adaptation of Rapid Contextual Design called Rapid Contextual Evaluation in a small scale field evaluation of a course administration system.

Gender Differences in Web Navigation

This paper presents the results of the first study in a series of experiments that were designed to examine gender differences in web navigation. In this study participants were asked to locate the answers to ten questions via navigation through a large university website. A variety of behavioural and self-report measures were used to examine gender differences in navigational efficiency, navigational strategy and user confidence. The results show that although there were no overall differences between males and females in terms of navigational efficiency, male participants expressed a significantly greater degree of confidence in their ability to navigate through the web than female participants. The results also show that gender differences are apparent in the types of navigational strategies used, with female participants relying predominately on landmark information to guide their navigational choices. These results are discussed in relation to their implications for the design of web-based navigational aids that support the differing navigational strategies favoured by male and female users.

Emotion faces: the design and evaluation of a game for preschool children

We describe the design and initial evaluation of an interactive game that enables preschool children to practise a basic social skill: emotion recognition. Users construct faces to represent 5 basic emotions through the manipulation of individual face parts. An iterative user-centred design process was used to gather image and sound data for the game. A field evaluation revealed that the children (7 boys and 4 girls) enjoyed playing the game and were able to match facial expression to emotions. Girls employed a different approach to game play than boys and achieved a higher success rate but made fewer overall attempts. Affective and co-operative activity was evident with the children showing joint attention and mirroring of emotions during play.

Design requirements for persuasive technologies to motivate physical activity in adolescents: a field study

Technology probes were used to investigate what adolescents would find persuasive in digital devices supporting opportunistic (unstructured/unplanned) exercise. The probes comprised pedometers, handheld consoles with an exercise game and a customised social website with an exercise focus. Three groups of six adolescents participated in the field study. To contextualise the study their attitudes to exercise, and exercise behaviours, were collected at the start and end of the study. The participants logged their daily exercise and noted any barriers that they encountered over six weeks. They reflected on these experiences and took part in innovation activities to identify requirements for motivational exercise technology. Analysis of the results revealed that they desired individual customisation of devices that can capture a wide range of physical activity data. Moreover, social interaction is expected within digital media and positive messages reinforcing goal attainments are valued, whereas negative feedback demotivates. These findings support those reported in other studies of both children and adults. More specific to this age group was their openness to sharing information beyond their friendship groups, although this was counterbalanced by their lack of autonomy in the physical world. This highlights issues that could constrain the effective design of technology for this age group.