Abstract
The main difficulty in the usability evaluation of a product concept or a
prototype is that it is very difficult to take reliably into account many
different characteristics or attributes, which cannot be measured with the same
unit, scale or instrument. Secondly, evaluation always involves some
uncertainty. One can never be really sure that all the essential aspects that
affect the final user emphasis are taken into consideration. This uncertainty
can be decreased by involving diverse people in the evaluation process during
R&D or, before the final decision, by elaborating the best ideas to a level
at
which they can be really used on a pilot scale in the field. Most often, though,
the latter takes too much time and would result in many other problems.
Evaluation can possibly be best enhanced by using enough involved people, i.e.
various experts and especially end-users, who need or use the product in
question. A key ingredient to the success of product development, in addition to
ergonomic knowledge, is often thought to be active involvement of the intended
product users by (1) measuring user-product interaction and (2) participation in
design decisions. When a potential end-user experiments with the product, both
quantitative and qualitative evaluation methods can be used. This thesis shows
some methodological possibilities of evaluation, especially through simulation.
It also describes in detail the practical phases of the experiments. For
example, a lot of development was needed to find out how to communicate product
alternatives and their concepts to (elderly) users. And most importantly, this
thesis aims to give evidence of how the procedure called experimental ergonomic
evaluation (EEE) should be feasibly implemented and statistically confirmed for
significance and consistency.
A special focus in the experiments was placed on elderly end-users.
Since the number of elderly citizens is increasing, there is a need for products
to help the elderly live independently at their homes. Studying and
understanding how users accomplish their tasks helps to identify their needs and
to formulate implications for the design of technology to satisfy those needs.
Thus, user studies conducted before beginning to design a new technology provide
a proactive way of involving users in the design process. The first prototypes
then enable usability studies, such as user trials. With an emphasis on
usability engineering, trials can be developed into more feasible EEE procedures
for industrial companies.
All the developed and applied EEE procedures were based on a user-centred
approach with different user trial types (N = 15). The users as subjects (N =
264) performed as real tasks as possible and, based on their perceptions during
the trials, gave their preferences or scored certain variables. The subjects
were also observed and measured by the researcher. The products or other
technologies in the trials comprised a total of 9 cases, ranging from "low-tech"
steps and chairs to "high-tech" information and communication technology (ICT)
applications. The perceived preference and observed performance measures were
then combined. Different methods are needed simultaneously to make the results
more accurate. The present EEE procedures proved to be cost-effective, efficient
and sufficiently valid at least in a research context.
The EEE procedures ranged from subjective estimations, such as rating and
ranking, to more complex multi-criteria methods that can be used to facilitate
decision-making, such as conjoint analysis, Mitchell's paired comparison and
use-value analysis. Objective evaluation was also used, including measurement of
products and users as well various observations. Both experts and end-users
(subjects) had their own important roles in the experiment. Based on this study,
EEE procedures are easy to implement in industry for routine usability testing
in the course of product development. EEE with its wide coverage yields more
universal and absolute usability values, not only ones based on direct
benchmarking.
| Identifer | oai:union.ndltd.org:oulo.fi/oai:oulu.fi:isbn951-42-5937-8 |
| Date | 28 March 2001 |
| Creators | Kirvesoja, H. (Heli) |
| Publisher | University of Oulu |
| Source Sets | University of Oulu |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/publishedVersion |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess, © University of Oulu, 2001 |
| Relation | info:eu-repo/semantics/altIdentifier/pissn/0355-3213, info:eu-repo/semantics/altIdentifier/eissn/1796-2226 |
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