Since MYCIN, explanation has become a fundamental feature of knowledge-based
systems (KBS). Among the common deficiencies of KBS explanations, the most acute one is the
lack of knowledge. This dissertation research investigates the use of explanations provided with
hypertext for increasing the availability and accessibility of domain knowledge. The ultimate
objective is to determine the behavioral and cognitive basis of the use of hypertext in providing
KBS explanations.
Two informationally equivalent KBS were comparatively studied in a laboratory setting:
one used hypertext to provide explanations, while the other one used conventional lineartext. The
experiment involved 26 experienced professionals, and 29 undergraduate and graduate students
specializing in accounting. Subjects used the experimental KBS to work on a realistic problem
of financial analysis. Both the process and outcomes of explanation use were assessed. Outcome
variables included improvement in decision accuracy, trust in the KBS, and perceived usefulness
of explanations. In addition to questionnaires used to measure decision accuracy and perceptions,
computer logs were used to capture the number, type, and context of explanation use. Thinkingaloud
procedures were used to assess the nature of explanation use.
Results indicate that the use of hypertext for providing explanations significantly improved
decision accuracy, and influenced users' preference for explanation types, and the number and
context of explanation requests. Enhanced accessibility to deep explanations via the use of
hypertext significantly increased the number of deep explanations requested by both novices and
experts. Verbal protocol analysis shows that the lack of knowledge and means of accessing deep
explanations could make it difficult to understand KBS recommendations, and that deep explanations could improve the understandability of KBS advice, especially in cases where
unfamiliar domain concepts were involved.
In the hypertext group, about 37% of the deep explanations were requested in the context
of judgment making, rather than in the abstract. While only about 28% of the deep explanations
requested by the lineartext group were the How type, 42% were the How type for the hypertext
group. Experts and novices had different preferences for explanation types. Experts requested a
much higher percentage of How, and lower percentages of Why and Strategic explanations, than
novices. Verbal protocol analysis illustrates that experts and novices used explanations for
different purposes.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/7511 |
| Date | 11 1900 |
| Creators | Mao, Jiye |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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