Contingency design is intercepting and preventing error
scenarios. These are situations where website visitors get in trouble, for
example on a 404 Error – File Not Found page. It is designing for when things
go wrong. It is the process of making sure that when something goes wrong, you
inform the user in an understandable and friendly manner.
The thought behind contingency design is that there is no
perfect website, even if you undertake thorough testing. Visitors of websites
will always run into trouble, by their own acting, or by a fault in a website.
Contingency design offers visitors help to solve the problems that they have
run into. It is about the error messaging, graphic design, instructive text,
information architecture backend systems and customer service that helps
visitors get back on track after a problem occurs.
The advantage of contingency design is that it will not only
improve the usability of a website. It is mainly aimed at reducing the
frustration of visitors. A website that offers help at the moment a visitor
runs into a problem can count on a higher satisfaction en loyalty, thus
improved conversion rates and revenues.
404 error – This is one of the most important contingencies
to cover. It is wise to spend a lot of time on your 404 error page to ensure
that it does an excellent job of helping your misguided visitors get back on
track. This page should be a nice design which fits into your overall site
theme. It’s goal is to tell your visitor what happened (or what may have
happened) and provide some alternative ways to find out what they want. It is
very wise to create individual error pages for each and every one. Other error
codes can be especially confusing to some visitors so it’s best to go out of
your way to help them out.
If you have an on-site search engine, be sure and spend some
time on your search failure page. You want to help your visitors when they
search but find no matches.
This is a little tougher, but when someone includes
incorrect data on the form it’s quite common to simply say "bad data"
and force them to re-enter everything or guess what is incorrect. It’s much
smarter to clearly show exactly what is incorrect, and to allow the visitor to
enter only the incorrect data again instead of the whole form. When errors
occur (especially in forms) it would be better to make the mistakes stand out
when you redisplay so they can be easily picked out from the rest of the page. It’s
also a good idea to include helpful hints on how to correct the problem.
A simple but good example of how filling in a form can be
made easier can be found in this story on signing up for My Yahoo.
37signals has written a very nice white paper on contingency design, with good real life examples of what can go wrong or how it should be done. The most important part of the white paper is simply a list with 20 important rules for providing successful contingency
design. In my opinion this white paper is a must read for designers,
programmers, copywriters, and any other site decision-makers who want to
increase usability and customer satisfaction. It proves that
optimization of websites to become more profitable does not have to be very