Heuristic Evaluations

Heuristic Evaluation is a method for quickly examining an interface based
on a set of usability rules. A good list
of heuristics
was proposed by Jacob
Nielson and we will use them here. This article will discuss the role of
a heuristic evaluation in your design process.

The Role of the Heuristic Evaluation

One common mistake made by those practicing User Centered Design (UCD) as
they start to advance beyond the novice stage is that start to believe that
they know their users well enough without really talking to the users. They
make up a few user personas and use scenarios, they write up a few paragraphs
on their audience demographics and they think that they understand how their
users will think and act. Working with real users can be time consuming,
expensive, and frustrating at times and it is easy to start to rationalize
leaving them out of the design process. This means that they start to rely
too much on methods like heuristic evaluations that rely on usability principles
and rules rather than real user input and feedback.

There are many ways to keep this tendency in check. I recommend incorporating
real users into a well documented design process that you follow. If you
plan from the start to get real user input when defining user tasks, testing
navigation, labeling, and other parts of your design and when you look to
improve an interface you will be less likely to cut it out later.

How to Conduct a Heuristic Evaluation

These are best done as part of a team, if you are working alone you will
have to be extra careful about reading too much into your results. If you
can, use a checklist that contains a numbered list of usability heuristics
you will use. Go through the system you are analyzing methodically. You can
go through a web site or other system page by page, working through a hierarchy
or other logical ordering or you can work through a set of user tasks from
start to finish.

As you work you should make note of the location of each problem you encounter,
the relevant principles (helpfully numbered), and the severity of the problem
ranked on a scale that you find meaningful. This will allow you to quickly
organize your results into an effective report.

If you are able to conduct the evaluation as part of a group each member
should use the same checklist with the numbered heuristics and agreed on
scale for ranking the severity of problems. Have each person conduct a thorough
analysis on their own and then go through the same evaluation process as
a group. Having a projector to display the system rather than huddling over
a monitor makes this easier. Once you are done you can compile the results
to create a comprehensive list of the problems you have found. Entering them
into a spreadsheet or database can make sorting and organizing easier.

Reporting and Using Your Results

When you report your results it is helpful to break them down by severity
with the highest priority problems at the top. You can then order them by
principle or location depending on which is most relevant to your system.
This makes it easy to see what you need to spend the most time and energy
on fixing and what may get left off the to do list.

Remember that a heuristic evaluation is not the end of the process. Now
that you have located what you believe are the problem areas in the system
you are designing you can take two steps. You can conduct user tests using
tasks that will take users to the problem areas you found. This gives you
the opportunity to see how real users react to what you perceive as problems
areas. Sometimes the results will back you up but sometimes they will surprise
you. You can also use the results to correct egregious errors. When combined
with user tests or surveys a heuristic evaluation gives you some good ammunition
in your fight for funding for a project or justification for making major
changes a boss or client may object to.

Kevin Hall
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