Richard F. Dillon

User Needs Analysis and requirements engineering: Theory and practice

Several comprehensive User Centred Design methodologies have been published in the last decade, but while they all focus on users, they disagree on exactly what activities should take place during the User Needs Analysis, what the end products of a User Needs Analysis should cover, how User Needs Analysis findings should be presented, and how these should be documented and communicated. This paper highlights issues in different stages of the User Needs Analysis that appear to cause considerable confusion among researchers and practitioners. It is our hope that the User-Centred Design community may begin to address these issues systematically. A case study is presented reporting a User Needs Analysis methodology and process as well as the user interface design of an application supporting communication among first responders in a major disaster. It illustrates some of the differences between the User-Centred Design and the Requirements Engineering communities and shows how and where User-Centred Design and Requirements Engineering methodologies should be integrated, or at least aligned, to avoid some of the problems practitioners face during the User Needs Analysis.

Measuring the true cost of command selection: techniques and results

A technique that measures the impact of command selection on task time and errors is described. Users were timed while performing a drawing task, then while performing the same task with interpolated command selections. The difference between these times, consisting of both the time to select the command and to resume drawing, is the time cost of command selection. Several interface configurations were evaluated with this method including selected combinations of single mouse, two mice, voice and touch. Touch and voice input resulted in faster command selection times (approximately 1 sec) than any of the mouse conditions (approximately 3 sec).

On the reliability of usability testing

Six professional usability testing teams conducted a usability test on an early prototype of a dialog box. Altogether, they identified 36 usability problems. No problem was detected by every team, 2 were found by five teams, 4 by four teams, 7 by three teams, 7 by two teams, and 18 problems were identified by one team only. There was more agreement among teams in this study compared to a previous study [1] and there was more agreement among the teams on severe vs. minor problems. Implications for the cooperation between usability testers and their clients are discussed.

Proactive interference and the functional ablation hypothesis: more disconfirmatory data.

Abstract According to the functional ablation hypothesis, memories for which amnesia has been hypnotically suggested do not interact with other information in memory. This hypothesis was tested in 2 interrelated experiments. In Experiment 1,Ss high and low in hypnotic susceptibility were administered a hypnotic induction procedure and tested on a Brown-Peterson (e.g., Wickens & Gittis, 1974) memory task designed to induce proactive interference (PI).Ss were exposed to 10 blocks of successive 3-word lists. Within each block, all words were strongly related, and, therefore, lists presented early in a block interfered with the retention of lists presented later (PI “buildup”). Following the “buildup” of PI,Ss were administered either a cue to be amnesic for the previous words of a block or a cue to relax. Contrary to the functional ablation hypothesis, the amnesia suggestion did not produce a “release” from PI in high susceptible hypnoticSs. In other words, the amnesia suggestion did not prevent previously l...

The role of response confusion in proactive interference

In two experiments using the Brown-Peterson memory paradigm, various instructions to guess had small effects on recall, but sizeable effects on the incidence of prior list intrusions. Subjective confidence ratings indicated that prior list intrusions were generally known to be incorrect. In Experiment III, 24 subjects, who were required to recall items from the present and immediately preceding trial on each of 16 trials, recalled present trial items at the same level as subjects under normal conditions. Correlation analyses, intrusion analyses, and confidence rating analyses indicated no relation between recall of present and previous trial items. These results indicate that proactive interference is primarily the result of inability to generate correct items, rather than confusion between present and previous items.

Analysis of retrieval cues and release from proactive inhibition

One hundred and forty-four subjects, divided into six groups, received four Brown-Peterson trials with recall triads from a common encoding category (e.g., cities). Items on the first three trials were from a common subset (e.g., eastern Canadian cities). On Trial 4, the subset was either shifted or not. No subset cue, or a subset cue at presentation or at recall, was provided to different groups on Trial 4. A subset shift resulted in improved recall, and a subset cue enhanced performance whether there was a shift or not. The results indicate that the cue influenced response generation, not response selection, and that there is no evidence that subset information was encoded when items were presented. The results do not imply a retrieval explanation of proactive interference.

Human factors in user-computer interaction: An introduction

The goal of human-factors research on human-computer interaction is to make computers usable. Describing the issues that determine whether a system is usable or not provides an introduction to the type of problems with which human-factors specialists are concerned.

Psychological research on videotex

Videotex is considered to be a powerful, but simple to use, computer network available for use in homes, offices, and schools. Information in the form of text and color graphics can be requested and displayed on the user’s television set. While retrieval of information is the first service provided on videotex, many other services, including electronic mail, electronic shopping, and electronic funds transfer, will be developed. However, in order to achieve the popularity predicted for videotex, a number of human factors and social problems must be solved. Research concerning some of these problems, and the role psychologists can play in their solution, is described.

Goal Setting And User Testing To Ensure A PACS Interface Satisfactory To Radiologists

To be successful, a Picture Archiving Communication System (PACS) workstation must have a user interface which is easy for radiologists to use. This paper describes the iterative design methodology used in the Integrated Radiology Information System (IRIS) project to achieve an easy to use system. Iterative design involves the radiologists in the design effort throughout the project. Iterative user interface design requires a number of activities: goal setting, identification of important user interface issues, prototyping, structured user testing, evaluation of user-test results against the goals, and further prototyping if the goals are not met. These stages are described in detail with examples taken from the IRIS project.

Videotex and the disabled

Abstract The potential of videotex for use by the disabled, and problems in the use of videotex by the disabled are summarized and discussed. Videotex is a system which allows users to access a powerful central computer over the telephone lines using a keypad or keyboard for input and a colour television set for output. In the home, office or hospital, the disabled will have access to information retrieval, electronic mail, teleshopping, games and computer aided instruction, as well as environmental monitoring and control using widely available, low cost equipment. The special problems of input and output of videotex by blind, deaf and motor impaired individuals are discussed. Various hardware (i.e. equipment) and software (i.e. programming) techniques to overcome these problems are described.