Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC

Anais do IHC’2001 - IV Workshop sobre Fatores Humanos em Sistemas Computacionais 75
perform the same typical tasks and to follow the same guidance given to non-expert
evaluators.
After reducing all usability problems, described by all evaluators, to a list of unique
problems, the researcher asked the participants to assign a severity rating to each problem
listed, according to the following scale:
• 0 - this is not a usability problem;
• 1 - low severity problem (cosmetic);
• 2 - moderate severity problem (obstacle);
• 3 - high severity problem (catastrophe).
Research Results and discussion
During the usability inspection of the sample corporate portal, 56 web pages were visited.
The participants of this research reported and described 701 usability problems, which
were reduced to 120 unique problems, after verbal logic analysis of all descriptions. The
unique problems were associated to numerical codes categorized into seven usability
factors, derived from usability heuristics defined by Nielsen (1994):
• Consistency;
• Context compatibility;
• Error prevention;
• Flexibility and efficiency of use;
• Aesthetics and simplicity;
• User control;
• Visibility, recognition and conduction.
Due to overlapping between usability factors, 14 usability problems were classified
in more than one category. For this reason, the total of usability problems, in some aspects
of this data analysis, may be 134, corresponding to 14 duplicated problems added to the
previously mentioned total of 120 unique problems.
Most of the usability problems reported (68%) were considered of moderate
severity, according to evaluators' answers. 'User control' and 'Error prevention' problems
got the highest average severity ratings (1,93 and 1,69, respectively - in a scale from 0 to
3). This result is compatible with Nielsen's statement : error situations or actions that do not
follow user's commands are critical for usability because they represent situations where
the user is in trouble and potentially unable to use the system to achieve the desired goal
(Nielsen, 1993). Therefore, web pages need to behave according to user expectations,
responding to his commands and mouse clicks, and avoiding errors. Otherwise, users may
give up using the corporate portal to search information or to complete specific tasks.
Based on evaluators' opinions, context compatibility, legibility, efficiency,
effectiveness and attractiveness were the positive aspects of the sample corporate portal.
On the other hand, the confusing design of this web portal was the satisfaction item that
reached the highest percentage of negative scores (40% of the evaluators' answers), for
being such a usability obstacle to the completion of the typical tasks (17% of the evaluators