Brought to you by EarthWeb
IT Library Logo

Click Here!
Click Here!

Search the site:
 
EXPERT SEARCH -----
Programming Languages
Databases
Security
Web Services
Network Services
Middleware
Components
Operating Systems
User Interfaces
Groupware & Collaboration
Content Management
Productivity Applications
Hardware
Fun & Games

EarthWeb Direct EarthWeb Direct Fatbrain Auctions Support Source Answers

EarthWeb sites
Crossnodes
Datamation
Developer.com
DICE
EarthWeb.com
EarthWeb Direct
ERP Hub
Gamelan
GoCertify.com
HTMLGoodies
Intranet Journal
IT Knowledge
IT Library
JavaGoodies
JARS
JavaScripts.com
open source IT
RoadCoders
Y2K Info

Previous Table of Contents Next


4. RECENT STUDIES OF THE USE OF EXPERT SYSTEM EXPLANATIONS

Several recent studies have focused on the empirical evaluation of the use of explanations as part of the user-ES interface. As their findings hold significant implications for designers of explanation facilities, they are summarized in this section. They are primarily useful in the sense that they signal the situations in which the provision of ES explanations is potentially useful to users.

Lamberti and Wallace (1990) investigated interface requirements for knowledge presentation in knowledge-based systems. They examined interactions between user expertise, knowledge presentation format (procedural vs. declarative formats), question type (requiring abstract vs. concrete answers), and task uncertainty, in terms of the speed and accuracy of decision-making performance. They found that for highly uncertain tasks, response time and accuracy for questions with declaratively formated explanations (as compared to procedural ones) were better for higher skill users. However, for low uncertainty tasks, the low-skilled subjects performed equally fast, but more accurately than high-skill users, when presented with declarative explanations to questions. Also, for explaining the procedures used in strategies of problem solving, both high- and low-skill users felt more confident with procedural explanations in contrast to declarative explanations. In relation to concrete vs. abstract knowledge organization, the study found that low-skill users performed significantly faster and more accurately when answering questions requiring concrete knowledge organization. High-skill users performed faster, although not necessarily more accurately, when responding to questions requiring abstract knowledge organization, in contrast to concrete knowledge organization.

Lerch et al., (1990) focused on some effects of the use of ES explanations. They measured user agreement with, and confidence in, conclusions presented by an ES. Subjects were told that these conclusions were obtained from one of three different sources of advice: novices, experts, or a knowledge-based system. As well, they used three different treatment conditions: no explanations provided, explanations provided in the form of English sentences, and explanations provided in production rule form. They found that while the use of explanations had an impact on the level of user agreement with the conclusions, it did not change users' confidence in the source of advice on which the conclusions was modeled. The different types of explanations were not considered in this study; rather, a generic category closely resembling the How explanation was used.

Ye and Johnson (1995) had subjects evaluate explanations presented in a fixed sequential order and compared user perceptions of usefulness and user preferences for the three different types of explanations. They found that the use of explanations had a positive effect on user agreement with ES conclusions, and that the Why explanation was the most preferred explanation across levels of user expertise and types of inference used for heuristic classification tasks. As well, experts and novices were found to have differing perceptions of usefulness for the various types of explanations presented. Experts perceived the How explanation as being most useful, and novices the Why explanation.

Dhaliwal (1993) studied the use of explanations in a judgmental decision-making situation involving the use of an ES that provided explanations. He found that users utilized ES explanations and that both experts and novices valued such explanations. While experts utilized the How explanations most extensively, novices used Why explanations most often. It was also found that feedback explanations were used more than feedforward explanations and that their use had a positive impact on the quality of decision-making. The study also found that users utilized explanations the least when their agreement with the ES was either very low or very high.

These studies have focused on various critical aspects of the ES explanation facility. They suggest that in designing an explanation facility, designers must pay careful attention to user perceptions for the three different types of explanations; the levels of source credibility; the content of explanations; as well as user agreement with the ES.

5. FACTORS INFLUENCING THE DESIGN OF EXPLANATION FACILITIES

Given the current state of ES explanations research, it is evident that designers of ES explanation facilities must pay careful attention to a host of factors that impact the design process. They can be classified into four distinct categories relating to the characteristics of: (1) the task setting in which explanations are used, (2) the nature of the explanations that are provided, (3) the interface design and explanation provision strategies used, and (4) the individual users of the ES.


Previous Table of Contents Next

footer nav
Use of this site is subject certain Terms & Conditions.
Copyright (c) 1996-1999 EarthWeb, Inc.. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of EarthWeb is prohibited. Please read our privacy policy for details.