Quality criteria for public cultural Web applications: recommendations and guidelines
2 Minerva
quality criteria framework for Web applications
2.2.1
Contents
2.2.1.1 Content sources
2.2.1.1.1 General
Content Sources
2.2.1.1.2 Institution
Contents
2.2.1.1.3 Domain
Contents
2.2.1.1.4 Application
Contents
2.2.1.2 Contents organization
2.2.2
Navigation
2.2.2.1 Use of Links
2.2.2.2 Backtracking soundness
2.2.2.3 Context Evidence
2.2.2.4 Media Control
2.2.2.5 Search usabilità
2.2.3 Design
2.2.3.1 Text and fonts
2.2.3.2 Visual layout
2.2.3.3 Use of graphics
2.2.3.4 Use of Media
2 Minerva quality
criteria framework for Web applications
Quality criteria
can be divided into two main groups: general criteria and specific
criteria. In this chapter we deal with the first, synthesizing the
main criteria adopted for the realisation of quality Web applications.
General criteria are divided into two categories: Accessibility
and Usability.
These two macro-criteria
must be co-ordinated in as much as they are inter-dependent.
2.1 Criteria
for accessibility
This is the
primary aim of a PCWA, which must ensure access to its cultural
contents for the widest possible number of users, regardless of
age, ability, available technology, education and culture.
One of the specific
aims of the eEurope Action Plan 2002 is to make every effort to
render the contents of the Web sites of Public Administration accessible
to disabled users. All recommendations on the subject indicate the
adoption of the Guidelines in the Web Accessibility Initiative (WAI)
and the World Wide Web Consortium (W3C) as being indispensable for
fulfilment of this goal.
The Web Content
Accessibility Guidelines v.1.0 (WCAG 1.0) issued on the 5 May 1999
are particularly relevant to the accessibility of the contents of
Web sites. While not all Member States have formally adopted the
WCAG 1.0 for creation of their public Web sites, it is universally
accepted that these must conform to level A in the Guidelines. Clearly,
this condition of minimum conformity must also be applied in the
planning of Public Cultural Web Application.
PCWA´s
however, have particular characteristics that on the one hand distinguish
them from other public sites, and on the other, paradoxically, could
obstruct the attainment of true accessibility. The goals of a PCWA,
for example, are aimed at specific users who, by definition of the
goal, present different motivations and needs for using the PCWA.
Consider for
example, goal number 6 "Spread cultural content" and its
three informative levels:
- supply basic
information and knowledge;
- supply advanced
information and documentation on the training and educational
activity and on support for cultural tourism;
- make available
complex and georeferenced data banks for training, scientific
research, and territorial administration and planning,
In the planning
and realisation of a web site which intends following this goal,
it is essential to consider that the language used and depth of
the material will differ according to whether the information is
basic, advanced or at the level of scientific research.
Pre-creating
information paths that cater for the differing needs of users can
help face this problem.
However, the
user profile imagined by the planner is almost always far from reality.
In the case
of disabled users, "simulated disability" should be used
in the planning stage. "Assistive" technology (for example
vocal synthesisers, screen enlargers etc.) should be used in the
laboratory and applied with technical correctness when this is required
by the checkpoints in the Guide Lines.
Consider point
14 of the guidelines of the WCAG: "make sure that documents
are clear and simple" and its relative check point 14.1 (priority
1 - level A):
"Use the
clearest and simplest language possible which is suited to the content
of a site"
A concrete application
of this check point in the case of a PCWA aiming to realise goal
n. 6 would seem therefore, to be problematical.
Further difficulties
could be met when trying to apply the checkpoints of the Guidelines
to other goals of the PCWA and there may not be merely technical
solutions.
One solution
would be to use a planning methodology suggested by engineering
of usability:
- create a
panel of disabled and professional users; the two categories of
users should be as representative as possible in terms of their
needs;
- said panel
should directly participate in the planning of the site,
giving constant evaluation on the ease of use;
- Type of use is defined within the context of the goal that is under consideration and of the WCAG. The PCWA should aim to reach the level of conformity established by the standards given by the Member State of the PCE that creates it. In the absence of specific standards, the minimum level of conformity should be level A.Type of use is defined within the context of the goal that is under consideration and of the WCAG. The PCWA should aim to reach the level of conformity established by the standards given by the Member State of the PCE that creates it. In the absence of specific standards, the minimum level of conformity should be level A.
Once the site
is on-line, the panel becomes an observer of the use of the site
in order to continuously improve and update it.
A further approach
is to use the Pattern paradigm (better known as Language of Pattern)
to deal the relevant problems with the realizations of Accessible
and Usable PCWA.
The Pattern
Paradigm was developed at the end of the ´70 by Christopher Alexander,
a professor of Architecture at the Berkeley´s University, to solve
the relevant problems about town planning and building. Alexander
started from the consideration that the low quality of the architecture
of the ´60 was bound to lack of formal methods of planning. In practise,
he founded that the town planning and building didn´t considered
the concrete experiences that were repening and without whose the
same projects were finishing to be extraneous to the real users
needs. Hence the idea to define models that fix a relation among
a context, a whole of conditions (or ties) bounded to that context
and solution that resolve the problem with those conditions and
in that context; the whole of those patterns forms a language (the
pattern language) that can be used from the architect to create
his projects.
In ´90 the idea
of the Pattern Language had a new impulse thanks to the big success
of his application in the field of software engineering and for
the planning of the "object oriented" (cf. "Design
Patterns" written by Erich Gamma, Richard Helm, Ralph Johnson
and John Vlissides).
Recently this
methodology has been applied also in the field of Human Computer
Interaction (HCI), with extents to the World Wide Web.
So Patterns
can give in a strict way the description of the experiences of a
planner through the formulation of a solution to a common problem.
What is peculiar
to this approach is the choice of not to give solution "pre-codified"
to the problem, rather trying to describe correctly both the context
and the approach, keeping under one title the experiences and the
solutions adopted (also by others) in similar situations.
"The Language
of Patterns is nothing else that a strict way to describe the experience
of somebody else" (C. Alexander).
The patterns
could seem an academic way to present guidelines for the solution
of problems inside a certain context, in our case, for example,
the WAI guidelines on web Accessibility.
It isn´t like
this for almost two reasons.
The first reason
is that patterns try to find the problem and they purpose the solution
independently from how this solution will be realized (with which
technical instruments and/or which products).
The second reason
is that the use of patterns means a particular attention to the
whole planning process rather than one component of the project,
like generally it happens with the guidelines.
A good pattern
will change on the planning experience (positive or negative) in
which will be used and on the observations that the planner could
do about its use.
Finally, patterns
and guidelines complete and integrate themselves: the ones giving
an approach more projectual, the others giving solution more practical.
The following
technical actions should become common praxis:
- check the XHTML code of every page before publication;
- check style sheets at the moment they are created and every time they are modified;
- check every page with different graphic browsers and with different versions of the same browser, making sure that there are no significant differences in visualisation, especially with regard to visual effects, page layout, functioning and navigation;
- check every page with text browsers;
- check every page for accessibility using the appropriate validates, paying particular attention to manual checks (which are, in any case, obligatory).
TOP
2.2 Criteria
for usability
This includes various aspects which are listed below and are dealt with and analysed in the manual.
2.2.1 Contents
2.2.1.1 Content sources
2.2.1.1.1 General content sources
Some of this
criteria are better explained according to single application goals
on chapter 3 "specific criteria for PCWA".
Consistency
Consistency is a very general meta-principle for quality, which apply to all application dimensions
as well. For contents, it states that similar pieces of information
are "dealt with" in similar fashions.
Currency
The concept of currency relates to the time scope of the contents
validity. However, the idea of currency of information is a bit
more complex than just "is it recent." To be current,
information does not have to be "new"- sometimes older
information is still agreed upon as valid and reliable. Therefore,
the site should present the most currently available data and the
currency of the information must be appropriate for the specific
field or topic. The site should avoid the presence of outdated information.
The links that are used by the site should be up-to-date (e.g.,
avoiding the presence of links to empty or under-construction pages,
or ro "dead" or unavailable sites). In addition, currency
properties must be evident to the user. This implies that the time
scope of the contents validity is clearly stated, and that the maintenance
policy should be dated.
Completeness
The concept of completeness is strongly related to user profiles
and goals. It defines the level of information coverage of the application
with respect to the characteristics of the cultural subject and
of the intended users. By definition, completeness strongly depends
on the nature of the cultural subject, on the profile of the intended
end users, on the goals of both, and on the potential scenarios
of use. An application should not omit "crucial" information
(needed by all possible users) but the amount of available resources
should be appropriate and well balanced for the specific user needs.
It should cover all relevant aspects of a topic and lead into the
appropriate level of details for the specific topic and field, but
the appropriateness of the depth of a specific topic is relative
to the user needs. (For example, a "simple" user may need
less information than the user that is expert in a particular topic).
Completeness applies both to pieces of contents as well to links,
in the latter case referring to the amount of links that the application
provide to pages of external sites. (see also section "Navigation
Criteria").
Comprehensiveness
The information is clear and easy to understand. Again, this criterion
is usually strongly related to the user needs. The language complexity
should be appropriate for the cultural level, experience, and interests
of the end users. (According to Nielsen, "Speak
the user language" is one of the cornerstones of usability).
See infra Chapter 3 "specific criteria for PCWA"
Conciseness
This "rhetorical" principle mainly apply to textual contents:
texts should not be too long and redundant (reading on a computer
is much more tiring than reading on paper) and should convey the
key message using the minimum amount of words.
Richness
In some cases, richness of interesting information (many examples,
data, links to other resources…) and use of multiple media
to convey it can be an added value per se, even if it is not strictly
needed for the intended users. It may increase the "image"
of the cultural subject, stimulate interest and curiosity, and provide
reasons for the users to return. Still, the richness of multimedia
must be "appropriate", as discussed in the following criterion.
Soundness
of dynamic media
The use of multiple dynamic media (audio, animation, video, 3D graphics)
can enforce richness (see above). Still, the choice of media should
be "sound", in terms of the ":format" (e.g., as resolution,
indicative size or duration), appropriateness of the medium per
se and the rhetoric style adopted to convey the contents message.
Multilingualism
In an intrinsically global world, at least the crucial information
should be given in more than one language, to reach and appeal to
a the largest possible audience. The success and the popularity
of an application is strongly impacted by its amount of multilingualism.
The multilingualism allows the review and use of the site from individuals
of different nationalities, promotes and elects the cultural heritage
of each country outside its borders, respects and promotes the European
Strategies for the Information Society.
Accuracy
Accuracy has to do with the evidence of bias or mistakes at any
level, both syntactical and semantic. Textual contents should be
correct in terms of grammar, spelling, and composition. All types
of contents should avoid incongruities, non necessary duplications
and repetitions. Obviously misleading statements or outrageous must
be absent.
2.2.1.1.2 Institution
contents
All this criteria
are better explained according to single application goals on chapter
3 "specific criteria for PCWA".
Institution
image
The application should include all information needed to give to
the user a view of what the cultural subject is, its initiatives,
its organization. These information contribute to create a sense
of trust on the institution, and support the establishment of the
right "image" of the institution itself.
Institution
responsibility
It should be clear which cultural subject is behind the web site,
who has the responsibility for the overall site and in particular
for its contents (see also section Domain Contents and Web Site
Contents).
IPR policy
The application should include all information about the IPR strategy
and technology adopted by the cultural subject to protect the contents
sources made available in the application.
Advertising
policy
The advertising, if any, should not overshadow the contents and
if advertising is a source of funding it should be clearly stated.
The site should display a brief description of the advertising policy
adopted. Advertising and other promotional material should be presented
to viewers in a manner and context that facilitates differentiation
between it and the original material created by the institution
operating the site.
2.2.1.1.3 Domain
contents
All this criteria are better
explained according to single application goals on chapter 3 "specific
criteria for PCWA".
Authority/Responsibility
This criterion refers to the evidence of who (individual or group
of individuals) is the author of the domain contents and of its
competence in relation to the subject. Identification of the sources
(e.g., by means of valid up-to-dated references and bibliography)
should be provided.
Objectivity
Information should be "objective" and "politically
correct". Unsupported claims made by the authors, one-sided
arguments about controversial issues, "messages" by individuals
or groups with vested interest in the topic, should be avoided.
The application should clearly specify what are author´s personal
opinions (if any) and distinguish them from more objective, factual
information.
Uniqueness
In the world-wide proliferation of web application almost on any
cultural subject, providing domain contents which is unique, original,
peculiar, is a source of attraction and interest for the user, and
a good reason to return to the site.
2.2.1.1.4 Application
contents
Application
mission evidence
There should be some contents stating the mission of the application,
its main goals, its main target users.
Application
responsibility
There should be some contents which describes who is responsible
for which aspects of the web site (this is sometimes reported in
a section "Credits"). In particular - who is
responsible for the overall editorial aspects (see also section
"Domain Contents Criteria" - Authority/Responsibility)
- who should be contacted for further information, complaints, technical
support and help in general.
Maintenance
strategy evidence
There should be some contents which describes the maintenance strategy
of the web site, how frequently it has been updated, when the last
update occurred. See also General Criteria - Currency.
Technical
strategy evidence
There should be some contents that describes the technical aspects
of the site which improve the use of the application functionality,
including for example minimum resolution needed, requirements for
best resolution, optimal browser configuration, software packages/plug-ins
needed, expected performance and warnings on possible delays, online
help and FAQs. Also, it is essential to inform the user about the
physical size of the contents, if it is large. When a large file
can be downloaded, the user should be informed of its size before
the file begins downloading and should have the opportunity to cancel
the download.
2.2.1.2 Contents organization
The following criteria address
the quality of the logical organization and the structuring of contents.
Appropriateness
of grouping
Contents elements of a cultural web application are typically grouped
according to different criteria (e.g., theme, time, author…).
The information should be composed well and arranged logically and
consistently, but the appropriateness of organization criteria depends
upon other factors: the characteristics of the cultural subject
and the adherence to the end users level of knowledge, mental model,
and goals.
Appropriateness
of nesting
Groups of information are typically organized hierarchically, resulting
into a layered structure where the actual contents is on the bottom.
The levels of nesting should be intuitive, logical, intrinsically
coherent, and ease to understand. Once again, they must be appropriate
for the mental model and the goals of end users, the nature of the
contents domain, and the characteristics of the delivery channel.
Nested structures must support efficiency: the identification of
the needed information within the hierarchical structure of nested
groups must be performed successfully and quickly. For example,
the most relevant subjects for the user should not be hidden into
too nested groupings, and should be more directly accessible than
less relevant information.
Appropriateness
of splitting
Large amount of information can be divided into a set of individual
pages, but and each page should be self-sufficient, i.e., it should
cover a specific topic or aspect without the need to access a different
page to understand its core message. When a complex contents is
stored in a single page, good headings and short introductory synopsis
may help user to graph immediately the core information of the page.
Organization
evidence
The grouping criteria must be evident and the semantic relations
among group elements have to be evident to end users. They must
be explained to them. There should be some contents that describes
what a group of "contents objects" is about (using a synopsis,
a comment, as summary, etc.), how the contents has been organized,
what is the main contents that the user can find (and eventually
cannot find - to avoid creating wrong expectations), which languages
are available, and similar. Tables of contents and indexes, site
maps and similar elements are useful for providing global views
of the site organization (and for orientation and navigation purposes
too - see section on Navigation Criteria). Some perceivable visual
cues can be adopted - for example, different page backgrounds of
nodes to distinguish among different types of contents, or textual
labels to indicate the groupings to which current contents object
belongs. These cues are also useful for context orientation - see
section "Navigation Criteria".
Membership
evidence
In a group of elements, it should be clear for the user which are
the elements in the group, by means of proper descriptors (textual
or visual) that identify the group members. See also section "Navigation
Criteria"
2.2.2 Navigation
2.2.2.1 Use of links
Link evidence
The meaning of links should be clear, i.e., it should be easy for
the user to understand both the relationship represented by the
link and the link destination - before traversing it (expressive
link labels and link descriptors are useful for this purpose). In
particular, links to external sites should not just identified by
urls, but shortly described by meaningful labels or comments.
Link soundness
Links should only bring to relevant material (e.g., not to "inaccessible"
or expired pages). There should not be any "dangling link",
or link which brings to a missing page, or to a page "under
construction" (this misbehavior should be evident to the user
before the link activation, to avoid loading a useless or empty
page, or a page just containing an error message).
Link coverage
This criterion refers to the amount of links available to improve
efficiency of access. From a given starting point, users should
quickly locate and access the items that are needed for their task,
without navigating through non-relevant material; alternatively,
they should quickly discover that those items are not in the application.
Efficiency of access is strongly related to the organizational schema
adopted for the content (see section "Content Organization
Criteria) which is reflected by the links. But it is improved by
the presence in the pages of "non semantic" links to the
most relevant portions of the site (oftentimes called "navigation
bars", "landmarks" or "accelerators") which
speed up navigation by providing jumps to different portions of
the site.
2.2.2.2 Backtracking
soundness
Whenever the user reaches
a given point in the web site, it should be easy to access previously
visited points and to continue navigation without restarting the
session from scratch, or without scanning backward all the previously
traversed pages using the browser backtracking button. In particular,
in guided tours it should be clear what happens at the end of the
tour, and how to return to the starting point.
2.2.2.3 Context
evidence
This criterion refers to
the need for the user of understanding his/her current navigation
context, to reduce the risk of "getting lost in the hyperspace"
(a typical syndrome of large hypertextual structures). Users should
be always aware of the actual status of their navigation session,
they should be able to understand their current position within
the current cluster of objects they exploring and the entire application.
For this purpose, many hypermedia use active maps and overview diagrams,
with indications of the user´s current location (and of previous
steps), or some perceivable visual cues - for example, different
page backgrounds of nodes to distinguish among different types of
contents, or textual labels to indicate the groupings to which current
content object belongs.
2.2.2.4 Media control
Media
control soundness
This criterion refers to what we can call "navigation in the
small", i.e., interaction with multimedia element and modification
of their dynamic state. Media control soundness is the possibility,
for the user, to control the state or the behavior of multistate
media objects such as images (which can be zoomed in-out), video
or sound (which can be played, stopped, suspended etc.). The commands
designed for the user to manipulate the state of a multimedia elements
depend on the nature of the element (e.g., a picture can be zoomed
in or out, but the same commands make no sense for a sound) and
on its physical properties such as resolution, size, duration. Control
commands such as "start", "stop", "pause", "re-start", "forward",
"backward" are meaningful, in principle, for all dynamic element
slots, but a video or a sound comment might require no interaction
if they are very short. Ultimately, the degree of control must be
appropriate to both the nature of the medium and the actual need
of users, based on their experience with digital multimedia and
their goals in using the system.
Media
control evidence
Whatever multimedia control actions are offered, they should be
evident to the user, and their meaning and effects should be clear.
2.2.2.5 Search usability
Navigation is oftentimes
complemented by search mechanisms, that allow users to specify some
characteristics of the information they are looking for and to retrieve
a list of pages matching these characteristics. We will not discuss
here the aspects concerning the technical quality of the adopted
search engine (the soundness of the search algorithm and of its
implementation, which we consider a purely technical problem). We
will focus here on the features that directly impact on the ease
of use of the search, considering the following sub-criteria:
Comprehensiveness
of query forms
It should be clear for the users which characteristics they can
specify for the searched objects, and how they can be specified.
Different types of search specifications should be available for
different skill levels and preferences.
Comprehensiveness
of query results
It should be clear for the users which objects have been retrieved,
by complementing page address with short descriptors that identify
their meaning (see also Link Evidence Criterion).
Navigability
of query results
It should be easy to navigate the set of retrieved objects. Most
search mechanism only support "forward index navigation",
allowing users to access each of the retrieved page from the list
of search results. In some cases, there is no direct link to return
to the list of retrieved objects, unless using the browser back
option. A search should support the possibility of returning to
the last search results at any time, and also of navigating directly
across the retrieved objects, forward and backward, like in a guided
tour.
2.2.3 Design
2.2.3.1 Search usability
Readability
To improve the readability of the text an adequate font size should
be adopted, at least a 10-point font is necessary to achieve the
best possible reading performance. Research has shown that fonts
smaller than 10-point elicited slower performance from users. For
people over 65, it may be better to use at least 12 or 14 point.
Standards
Browsers display different default font types and sizes, depending
on the type of browser, browser version, and operating system the
browser runs on. The text sould be good displayed in the users browsers.
The default fonts for PC computers are Times New Roman and Arial.
For MacIntosh, the default fonts are Times and Helvetica.
2.2.3.2 Visual layout
Consistency
Users should not have to wonder whether different words, situations,
or actions mean the same thing. Once users see a link, they expect
when they see it again it will look the same, be in the same location,
and function the same. If it has changed, users may be forced to
relearn the button, which will delay their completion of tasks.
Maintaining consistency allows users to develop a set of skills.
Concepts can be learned once and then applied in a variety of situations.
Efficiency
The most efficient viewing and use of information should be ensured
on each page of the site. Developers should evaluate the most common
use of each page and make design decisions that ensure the best
possible performance.
Spatial
organization
Navigation and identity should be displayed in the top and left
areas of the screen Users are comfortable and familiar with this
design. The use of tables and images wider than the defined image-safe
area should be avoided, users often become annoyed if they have
to manipulate a horizontal scrolling bar to see contents.
2.2.3.3 Use of graphics
Minimalism
Pages should not contain elements which are irrelevant or rarely
needed. Every extra element in the web site competes with the relevant
and diminishes their relative visibility.
Use of
colours
When background and text colours are close to the same hue, they
may provide insufficient contrast on monochrome displays and for
people with certain types of colour deficits. The text and graphics
should be understandable when viewed without colour. Avoid to use
image as background colour, this may obstacle the users readability.
Graphic
file format
Different graphic file formats employ varying compression schemes,
and some are designed to work better than others for certain types
of graphics. The two primary Web file formats are GIF and JPEG.
All the images in the site should be in one of these compressed
format. A third format, PNG, has been available since 1995 but has
been little used because of poor browser support.
2.2.3.4 Use of media
User controls
The users should always have the control for all playable files:
Play, Pause/Resume, Stop, Rewind, Fast Forward and Volume. QuickTime
video and sound files automatically provide these controls. If other
types of media formats are used, a similar type of controls should
be created.
Use of
animations
Animation is a wonderful tool in web design, but in some cases can
be over-used. Animated graphics can be too big and too busy, If
there are too many animated elements, your page can be difficult
to read and information can be difficult to find. Lots of animation
makes your page take longer to load.
Objects
size
The size of media objects should not make the site heavy to download.
Instructions for downloading media objects should include the file
size, the media type, and a description of the subject matter. This
information will help users determine whether they want to wait
for the download.
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