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No copyright is
claimed. Edit this document to incorporate your own concerns
about usability, replace
the signature with your own, and post it prominently, preferably
with the title image.
The Goal of Usability
We hold this truth to be still obscure… that
the mandate of software usability is to reduce the need for
training to
zero. Though the overall goal of usability consists of equal
parts learnability and facility, the limiting factor in software
acceptance is not its speed and power, but its accommodation
to those who must learn to use it. That is the task and
expertise of the usability community, to help deliver systems
that incorporate
the entire training burden. While the pressure to produce products
immediately and with limited resources is inescapable, so too
is the competitive force ensuring that the prevailing products
will be those that are self-training.
The Tenets of Usable Design
Usability starts with and consists substantially
of simple, age-old communication principles painstakingly evolved
over
1500 years of producing the printed word:
- Communicate explicitly, actively, precisely, and accurately.
The first law of usability is explicitness. Don’t
require the user to translate, decode, search, or infer.
- For all software usability problems, even many hardware
problems, non-architectural solutions—often simple text
changes—can give users what they need. Don’t
compound problems with more technology.
- Provide both training for new users and ultimate facility
for those users once they become experienced, without compromising
either objective. Provide both character-based manipulation
and step-through dialogs.
- Provide all historical affordances and functions;
don’t
start over. Use frameworks.
- Present the more general items and earlier steps toward
the top and left. Promote broader or more important items
and demote more specific items.
- Group like items and segregate unlike items.
- When in doubt, provide multiple ways to access functions.
- Provide all sort orders for all information.
- When consistency provides guidance, use it. When it
is a hobgoblin, use distinctiveness to its advantage.
- When conventions apply, use them. When they do more
harm than good, be creative.
The Software Users' Bill of Rights
- We shouldn't have to read a manual to
use mass market software. For business software, the most
we should have to read is a booklet on the theory of operation.
- We should be able to accomplish
every task and entry with the fewest possible keystrokes.
We shouldn’t have to
enter 4-digits for the year. And 8,000 years from now we
shouldn’t
have to enter five digits.
- We should be able to do things
in whatever order we want. When it’s not the order
that is needed, the computer should direct us through the
necessary order.
- We should be able to make mistakes without
being terminated, executed, canceled, re-booted, or erased.
- We should be able to see and understand why the program
does what it does.
- We expect the computer to communicate
with us actively and noticeably, not implicitly or subtly.
- We expect all of what we type into the computer to
be saved, by default.
- We expect to be forewarned when any work is over-written,
undone, or erased.
- We expect to have most of our work retained after
the power is interrupted.
- We expect supporting information to provide explanations
and examples,not just what keys to press,
and to
concentrate
on exceptions and problems.
Implementing Usability
- Usability must be included as a role on all software
projects and owned by a specific individual. It
does
not have to be
full-time role and need not be on all but the largest projects.
- The usability role should answer directly to the highest
possible level of product management, so that quality
goals are side-by-side with cost and time.
- The Users Bill of Rights should be accessible from
the About function on all software projects.
- The statement should be included on product packaging and
literature that "This product endeavors to deliver the full
capability promised by the Software Users' Bill of Rights."
Jack Bellis, 2004-Jan-03
No copyright is claimed. Edit this document
to incorporate your own concerns about usability, replace
the signature with your own, and post it prominently, preferably
with the title image. |