How to Do a Heuristic Evaluation with Scores

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So, your team is about to launch a redesigned software application or web site. Out of nowhere your boss asks you: “What did you do to enhance usability? Is it more user-friendly? How do you know? Give me a report by end of today.”

You figure you ought to have some kind of criteria by which to judge the usability of the new design. Formal usability testing takes too much time and costs money. You might be wrong about that, but anyway, what do you do?

Your boss is busy and doesn’t want a bunch of details, just a number that sounds good. As in: “before we redesigned this application, it scored 47. We raised it to a 79.”

This guide will help you produce those kinds of numbers using methods that are repeatable, logical, defensible, and fast. What you want to do is called a heuristic review.

A euro-what?

In human-computer interaction, a heuristic is simply a defined characteristic of a good (or bad) user interface, based on the experience of an expert usability professional. A heuristic review, then, entails a usability specialist examining an application to identify potential usability problems.

A heuristic review is a shortcut method for usability evaluations, as opposed to a longer, more involved methods of evaluation that involve user feedback such as usability testing.

1. List the heuristics you’re going to measure

Begin by drafting a list of the characteristics you’re going to examine. Here’s a sample list:

  • Task orientation and website functionality
  • Navigation and information architecture
  • Forms and data entry
  • Trust and credibility
  • Quality of writing and content
  • Search
  • Help, feedback and error tolerance
  • Page layout and visual/aesthetic design
  • Accessibility and technical design

There is no single, industry-standard list of heuristics. But the lists found in these resources come pretty close:

If you have no prior experience with usability heuristic evaluations, here’s another excellent article to get your feet wet: 6 things you didn’t know about Heuristic Evaluations.

2. List the questions you’ll ask in regard to each heuristic

For each of the characteristics you listed in step 1, come up with a list of questions you’ll use to conduct the review. You can write as many questions as you like, just remember that the more questions you have, the longer the review will take to complete.

For example, when looking at the layout and visual design of a website, questions could include:

  • Are standard elements (such as page titles, website navigation, page navigation and privacy policy) easy to locate?
  • Is there a good balance between information density and white space?
  • Does the site / app have a consistent and clearly recognizable look and feel that will engage users?

Regarding written copy, questions could include:

  • Are the screens simple to scan on screen? Are they broken up by headings and subheadings? Are the paragraphs short?
  • Are acronyms and abbreviations defined when first used?
  • Does the website favor maps, diagrams, graphs, flow charts and other visuals over long blocks of text?

3. Devise your scoring system

A very simple scoring system might look like this:

  • 0 points if it falls short of a metric
  • 1 point if it’s halfway there
  • 2 points if it does the job

So, if standard elements appear most of the time on most screens, but not always, then the heuristic would score only 1 point. If the interface has plenty of white space and never seems too dense or cluttered, then it would receive 2 points.

You’ll notice that these are fuzzy judgement calls and opinions. You can (and should) be able to support your score with factual observations, but one reviewer’s “1″ might be another reviewer’s “0″ or “2.” The assumption is that you’re the usability expert; that’s why you’re doing the review. It’s your call. In this sense, heuristic review is a more subjective approach to usability evaluation than formal usability testing.

You can weight questions differently if you feel some criteria are more important than others relative to the heuristic. A more complex scoring scale might look like this:

Heuristic category 1

Question A: 0 – to – 9 scale

  • 0 points if it falls short of a metric
  • 3 point if it’s halfway there
  • 6 points if it does the job
  • 9 points if it’s out of this world awesome

Question B: 0 – to – 15 scale

  • 0 points if it falls short of a metric
  • 5 point if it’s halfway there
  • 10 points if it does the job
  • 15 points if it’s out of this world awesome

You can see in the example above that Question B is designed to factor more heavily into the overall rating for the heuristic category.

The numbers are up to you. But whatever you do, don’t change your scoring system if you are comparing two sites, or if you are establishing a benchmark against future evaluations of the same app. You must compare apples to apples for the system to be meaningful.

4. Evaluate and score it

If you’re doing this review by yourself, your evaluation form will be pretty simple:

Metric Possible Score
Page layout & visual design
30 19
Are standard elements (such as page titles, website navigation, page navigation and privacy policy) easy to locate? 10 9
Is there a good balance between information density and white space? 10 6
Does the site / app have a consistent and clearly recognizable look and feel that will engage users? 10 4

If you’re doing a group review with two or more usability specialists, just average everyone’s scores together.

Now, using the sum of points scored within each heuristic category, calculate a percentage score to give a quantifiable sense of what’s going on across the site, as shown here:

Heuristic Questions Possible Score Actual Score Result
Page layout & visual design 3 30 19 63%
Task Orientation 6 70 63 90%
Navigation & IA 15 54 29 54%
Forms & Data Entry 4 34 29 85%
Overall score 99 198 172 73%

In this example, our site scored 73 out of a possible 100 points. You can clearly see that the problem area is Navigation & IA, while Task Orientation has less room for improvement. Hopefully after restructuring the content and rethinking the navigation tools, the software team can pull that score up!

5. Visualize

“A picture is worth a thousand data points.” (See what I did there?) Radar plots or Spider charts are great for representing this kind of data set:


Ex. 1: A radar plot showing a website that performs well across all heuristic categories.


Ex. 2: A radar plot showing poor performance across all heuristic categories.


Ex. 3: A radar plot showing a website that performs well in all areas but one.


Ex. 4: A radar plot showing a website that performs poorly in all areas but one.

Pop that plot in your PowerPoint deck and get ready to wow ‘em!

Credit: radar plot diagrams from A Guide To Heuristic Website Reviews by Leigh Howells at Smashing Magazine

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Contributed by Ben Judy (4 Posts)

http://benjudy.com


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Comments

    • Ben Judy says

      Hi, Eric. I did give credit with a link at the end — “Credit: radar plot diagrams from A Guide To Heuristic Website Reviews by Leigh Howells at Smashing Magazine” Sorry if I should have been more clear about the source!

      I feel it’s worth pointing out that the five steps that form the main content of my article are my own. It’s not unusual to copy examples from other articles and give credit to where the examples came from.

      Thanks for reading!

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