"Even better than good error messages is a careful design
which prevents a problem from occurring in the first place. Either eliminate
error-prone conditions or check for them and present users with a confirmation
option before they commit to the action." (Jakob Nielsen, "Usability Engineering", 1993)
"Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large." (Jakob Nielsen, "Usability Engineering", 1993)
"A basic reason for the existence of usability engineering is
that it is impossible to design an optimal user interface just by giving it
your best try. Users have infinite potential for making unexpected
misinterpretations of interface elements and for performing their job in a
different way than you imagine." (Jakob Nielsen, "Usability Engineering", 1993)
"A problem with this 'waterfall' approach is that
there will then be no user interface to test with real users until this last
possible moment, since the "intermediate work products" do not
explicitly separate out the user interface in a prototype with which users can
interact. Experience also shows that it is not possible to involve the users in
the design process by showing them abstract specifications documents, since
they will not understand them nearly as well as concrete prototypes." (Jakob Nielsen, "Usability Engineering", 1993)
"Guidelines list well-known principles for user interface
design which should be followed in the development project. In any given
project, several different levels of guidelines should be used: general
guidelines applicable to all user interfaces, category-specific guidelines for
the kind of system being developed […] and product-specific guidelines for the
individual product." (Jakob Nielsen, "Usability Engineering", 1993)
"If users' needs are not known, considerable development
efforts may be wasted on such features in the mistaken belief that some users
may want them. Users rarely complain that a system can do too much (they just don’t
use the superfluous features), so such over-design normally does not become sufficiently
visible to make the potential development savings explicitly known. They are
there nevertheless." (Jakob Nielsen, "Usability Engineering", 1993)
"It is always better if users can operate the system without
having to refer to a help system. Usability is not a quality that can be spread
out to cover a poor design like a thick layer of peanut butter, so a
user-hostile interface does not get user-friendly even by the addition of a
brilliant help system." (Jakob Nielsen, "Usability Engineering", 1993)
"One should not start full-scale implementation efforts based
on early user interface designs. Instead, early usability evaluation can be
based on prototypes of the final systems that can be developed much faster and
much more cheaply, and which can thus be changed many times until a better
understanding of the user interface design has been achieved." (Jakob Nielsen, "Usability Engineering", 1993)
"Scenarios are an especially cheap kind of prototype. […]
Scenarios are the ultimate reduction of both the level of functionality and of
the number of features: They can only simulate the user interface as long as a
test user follows a previously planned path. […] Scenarios are the ultimate
minimalist prototype in that they describe a single interaction session without
any flexibility for the user. As such, they combine the limitations of both
horizontal prototypes (users cannot interact with real data) and vertical
prototypes (users cannot move freely through the system)." (Jakob Nielsen, "Usability Engineering", 1993)
"The concept of 'user' should be defined to include
everybody whose work is affected by the product in some way, including the
users of the system's end product or output even if they never see a single
screen." (Jakob Nielsen, "Usability Engineering", 1993)
"The difference between standards and guidelines is that a
standard specifies how the interface should appear to the user, whereas a set
of guidelines provides advice about the usability characteristics of the
interface." (Jakob Nielsen, "Usability Engineering", 1993)
"The entire idea behind prototyping is to cut down on the
complexity of implementation by eliminating parts of the full system.
Horizontal prototypes reduce the level of functionality and result in a user
interface surface layer, while vertical prototypes reduce the number of
features and implement the full functionality of those chosen (i.e., we get a
part of the system to play with)." (Jakob Nielsen, "Usability Engineering", 1993)
"The entire idea behind prototyping is to save on the time
and cost to develop something that can be tested with real users. These savings
can only be achieved by somehow reducing the prototype compared with the full
system: either cutting down on the number of features in the prototype or
reducing the level of functionality of the features such that they seem to work
but do not actually do anything." (Jakob Nielsen, "Usability Engineering", 1993)
"The most basic advice with respect to interface evaluation is simply to do it , and especially to conduct some user testing. The benefits of employing some reasonable usability engineering methods to evaluate a user interface rather than releasing it without evaluation are much larger than the incremental benefits of using exactly the right methods for a given project." (Jakob Nielsen, "Usability Engineering", 1993)
"The system should always keep users informed about what is
going on, through appropriate feedback within reasonable time." (Jakob Nielsen, "Usability Engineering", 1993)
"Usability engineering is not a one-shot affair where the
user interface is fixed up before the release of a product. Rather, usability
engineering is a set of activities that ideally take place throughout the
lifecycle of the product, with significant activities happening at the early
stages before the user interface has even been designed." (Jakob Nielsen, "Usability Engineering", 1993)
"User interfaces should be simplified as much as possible,
since every additional feature or item of information on a screen is one more
thing to learn, one more thing to possibly misunderstand, and one more thing to
search through when looking for the thing you want. Furthermore, interfaces
should match the users' task in as natural a way as possible, such that the mapping
between computer concepts and user concepts becomes as simple as possible and
the users' navigation through the interface is minimized." (Jakob Nielsen, "Usability Engineering", 1993)
"Users often do not know what is good for them. […] Users
have a very hard time predicting how they will interact with potential future
systems with which they have no experience. […] Furthermore, users will often
have divergent opinions when asked about details of user interface design." (Jakob Nielsen, "Usability Engineering", 1993)
"Users often raise questions that the development team has
not even dreamed of asking. This is especially true with respect to potential mismatches
between the users' actual task and the developers' model of the task.
Therefore, users should be involved in the design process through regular
meetings between designers and users. Users participating in a system design
process are sometimes referred to as subject matter experts, or SMEs." (Jakob Nielsen, "Usability Engineering", 1993)
"Users are not designers, so it is not reasonable to expect
them to come up with design ideas from scratch. However, they are very good at
reacting to concrete designs they do not like or that will not work in
practice. To get full benefits from user involvement, it is necessary to
present these suggested system designs in a form the users can understand." (Jakob Nielsen, "Usability Engineering", 1993)
"A general principle for all user interface design is to go through all of your design elements and remove them one at a time." (Jakob Nielsen, "Designing Web Usability", 1999)
"The web is the ultimate customer-empowering environment. He or she who clicks the mouse gets to decide everything. It is so easy to go elsewhere; all the competitors in the world are but a mouseclick away." (Jakob Nielsen, "Designing Web Usability", 1999)
"Ultimately, users visit your website for its content. Everything else is just the backdrop." (Jakob Nielsen, "Designing Web Usability", 1999)
"Developing fewer features allows you to conserve development resources and spend more time refining those features that users really need. Fewer features mean fewer things to confuse users, less risk of user errors, less description and documentation, and therefore simpler Help content. Removing any one feature automatically increases the usability of the remaining ones." (Jakob Nielsen, "Prioritizing Web Usability", 2006)
