The issue here is that there are many types or levels of consistency
that you need to consider. The basic types of consistency are:
Internal consistency - consistency in layout, controls, colors,
commands, features, sizes of objects and areas, and branding
External consistency - consistency with the user interfaces of other
products that people use together (for example, Cut, Copy, Paste)
Metaphorical Consistency - consistency of user interface objects
(individual or composite objects) with their metaphorical counterparts
and perhaps the most important category - Consistency with how people
work - the one that is sometimes lost in the push to be internally
consistency.
Each of these four categories can be broken down. Here is an
unordered list of some of the items that might go under the general
categories above:
For example:
• Visual inconsistencies
• Interaction inconsistencies (different ways to do the same thing).
• Control inconsistencies (for example, different pages on the same
Web site use different calendar controls).
• Inconsistencies between the system model and the user's mental model
(Grudin, 1989))
• Error prevention inconsistencies (for example, in one case you
provide a cue on the required format for phone numbers while
elsewhere, you have no cues and get an error message if you use the
wrong format)
• Terminology inconsistencies ("Login" and "Log in" are both used as
labels in different parts of the site or product and "sign-in" is used
in the Help for the product).
• De facto inconsistencies where a product does not follow common
designs, for example, the use of underlining to indicate that an item
is a link.
• Inconsistencies with corporate, legal, or technical standards. For
example, most large companies have clear rules on how trademarks are
to be displayed. Failure to be consistent in how trademarks are
displayed could, in rare cases, lead to a challenge on that trademark.
• Inconsistencies across different media (at a corporate level, this
can involve marketing materials, the documentation, technical guides
for support, advertising, and the software interface).
• Inconsistencies among versions for different languages or cultures.
• Inconsistencies across different platforms (for example, Web pages
on PCs, versus cellphones, versus PDAs for example).
So, in the example that Jeff gave, making a button larger might very
well be consistent with the way people work (they are doing hundreds
of operations a day and a larger button is an easier target and the
the default target 95% of the time - consistency with the way people
work though visually inconsistent.
When people speak of consistency, they tend to focus on visual and
basic interaction, but neglect the most important issue of consistency
with how people work.
There is an extremely important paper by Jonathon Grudin that
discusses how inconsistency can actually be consistency when it
supports the users work. This is a paper that doesn't get the
accolades it deserves for critical and deep thinking about
"consistency".
J. Grudin (1989) The Case Against User Interface Consistency. In:
Communications of the
ACM, vol. 32, no. 10, 1989, pg. 1164 - 1173. If you dig around, I
think that you can find a copy on the net. The paper is old, but the
examples can easily be applied to more modern interfaces as well.
A strong recommendation for those who are asked to "make the product
consistent" is to define what type of consistency is most important
given your personas/user groups, tasks (consider that the frequency
and criticality of a task can influence the design greatly and
possibly might require some visual or interaction consistency to
support multiple user groups.
I would invite anyone involved in your consistency projects to read
this article so they understand that consistency is not something
simple that you can just mandate without clear definitions.
Chauncey
On Tue, Oct 14, 2008 at 4:11 PM, Jeff Noyes <[EMAIL PROTECTED]> wrote:
> I'm so tired of this argument, and I'm hoping this group can help provide
> facts.
>
> I recognize that some things in the UI should remain consistent - like an
> interaction model. But often a deviation is required - ironically for the
> sake of usability. Maybe you need to enlarge a button to emphasize it's
> importance, or maybe the interaction model that worked 80% of the time falls
> down in some cases. For me, deviation is a battle with stakeholders outside
> of design. They want everything consistent. Because hey, consistency equals
> usability.
>
>
> Are their facts (white papers, reports, etc.) that suggest deviation is
> acceptible. Perhaps reports that show that consistency for your equaled
> poor usability?
> I recognize this is a loose request. Partially by design as I'd like to
> pull in a bunch of infromation.
>
> I'm all ears.
>
> Jeff Noyes
> ________________________________________________________________
> Welcome to the Interaction Design Association (IxDA)!
> To post to this list ....... [EMAIL PROTECTED]
> Unsubscribe ................ http://www.ixda.org/unsubscribe
> List Guidelines ............ http://www.ixda.org/guidelines
> List Help .................. http://www.ixda.org/help
>
________________________________________________________________
Welcome to the Interaction Design Association (IxDA)!
To post to this list ....... [EMAIL PROTECTED]
Unsubscribe ................ http://www.ixda.org/unsubscribe
List Guidelines ............ http://www.ixda.org/guidelines
List Help .................. http://www.ixda.org/help
