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Unformatted text preview: sured as part of a study to measure other usability elements. In order to
ensure enhance system usability, a system should have very low error rate, so that users
make few errors during system usage. In addition, catastrophic errors must not occur.
System users should try to control system error as much as they can. Some errors can be
corrected right away by the system users, without any effects other than to slow down
the transaction time. Such errors don’t need to be counted separately, since their effects
are included in the measurement of efficiency of use. (Nielsen 1993)
2.3.5 Subjective Satisfaction:
According to Nielsen (1993) subjective satisfaction refers to the extent the system is
pleasurable to use. User likeness is critical for system success; therefore the system
should be pleasant to use to achieve subjective satisfaction. Since, the subjective
satisfaction is an important usability attribute for the systems that are used on an
optional basis in a non-work environment such as computing games, interactive fiction
and creative painting. In such systems the entertainment value is significant as compare
to its speed to do things get done. Users should have an entertaining, dynamic and
continues enriching experience when using such entertainment systems since they have
no other objective.
Subjective satisfaction being a usability attribute is different from the issues of the
general public’s point of view about computers. People’s point of view toward
computers in general should probably be seen as a component of the social acceptability
of computer instead of their usability. Subjective satisfaction can be measured by
merely taking the users opinion about the subjective satisfaction of any system. From
single user perspective, the answer to such a question is subjective, however when
answers from multiple users are averaged together, the result is will be objective
measure of the system’s pleasantness. Since, the entire purpose of subjective
satisfaction usability attribute is to measure whether users like the system or dislike, it is
very suitable to measure it by asking the users. (Nielsen 1993) 2.4 Usability and System Acceptability According to (Nielsen, 1993) system usability is relatively a minor concern as compared
to the larger issues of system acceptability, which is the main question of whether the
system is good enough to satisfy user needs and requirements and other potential
stakeholders e.g. users, clients and managers. In general, acceptability of a computer
system is again a combination of its social acceptability and practical acceptability; for
instance, consider a system which investigates whether people applying for
21 unemployment benefits are currently employed or unemployed to prevent fraudulent
claims. This can easily be done by verifying information with other systems. Some
people might appreciate this fraud-preventing system whereas some people might
assume that it un-necessarily delays the benefits to deserving people. In this example,
the system is not socially acceptable by peoples of later category; even though the
system is practically acceptable since it prevent fraudulent claims.
According to (Grudin, 1992) if it is decided that the system is socially acceptable and
satisfied, we can proceed to analyze its practical acceptability within various categories,
including traditional categories e.g. cost, support, reliability, compatibility and system
usefulness. Here, system usefulness refers that the system should be able to achieve
desired objectives. In addition, it can be split into two groups as utility and usability.
Here utility refers to the question whether the functionality of the system mainly can do
what is desired and usability refers that how well users can use that functionality?
According to Mulligan (1998) usability applies to all aspects of a system with which a
human may interact including installation and maintenance system procedures. It is
uncommon to find a computer feature that really has no user interface components.
Even a system facility to transfer data between two computers will surely have an
interface to trouble-shoot if any error occurs.
A model of attributes of system acceptability
(Nielsen, 1993) Page 25 22 In this figure 2.2., A model of attributes of system acceptability is given which
illustrates the different elements of system acceptability. The model is based on four
key attributes, included social acceptability, practical acceptability, usefulness, utility
and usability, these elements are critical for the successful interface design. The main
features of system acceptability also include sub-elements that describe the details
against each key segment. 2.5 Principles to support Usability
Dix et al.,(1993) have defined general principles which can be useful to the d...
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