Phostir: The Traffic Light Usability Testing Tool

by Sharon Hurley Hall

Last updated on December 28th, 2017

Can a traffic light system help you troubleshoot and resolve web usability issues?

That’s what Phostir promises. It was recently featured in our roundup of web usability tools and I decided to take it for a full test drive to see how it worked.

Let’s get one thing out of the way early. The name is pronounced FOE-STEER and it comes from the Greek word for light. In other words, it’s shedding light on what’s happening with your website.


Getting Started

Getting setup with Phostir is a simple process and only takes a few seconds. Sign up with your Facebook, Google or LinkedIn accounts or with email, then you get a snippet of code called the Phostir tag, which needs to go at the bottom of every web page you need to track.

There are different ways to do this. Since I use the Genesis theme on my website, I just placed the code in the appropriate box in the theme dashboard but there are on-site instructions for installing it manually or via a tag manager.

I was impressed by how quickly I started seeing site data. With some analytics programs, you have to wait a day or more for usable data, but with Phostir I got actionable data almost immediately.

The top of the dashboard gives a running total of the number of page views analyzed in the last 24 hour period. There’s also an at a glance view of the breakdown between desktop and mobile users. And the dashboard has two tabs for different views of your data. One is titled “Prioritize” and the other “Analyze.”

Exploring the “Prioritize” Dashboard

The main part of the prioritize dashboard is the traffic light system that identifies the number of errors on the pages people have accessed. If there’s one error or less, there’s a green band, with between 2 and 5 errors in the orange band and more than 5 errors in the red band.

You can use this information to tackle the areas with the highest number of errors first, immediately improving the user experience (UX).

However, Phostir has another clever feature. It analyzes your own traffic to determine which pages are high, moderate and low usage pages.

That means if you tackle the errors in the red zone on the high usage pages you will make a measurable and positive difference to how users interact with your site.

The on-screen instructions make this process transparent, telling you where you will get the most impact.

In this case, clicking on the red area took me to a sub-page which told me more about how users were experiencing the home page of my site. Since my blog’s been online for more than seven years, I was expecting some of the content to be non-compliant with current optimization norms. I was right.

Phostir errors

On the home page, Phostir suggested shortening titles, adding alt text and changing HTML code.

In looking at another page, the tool suggested an improvement (getting rid of a pre-ticked box) that I didn’t even see when logged in.

Phostir also highlighted that not all images had alt text, so I found a WordPress plugin to help me address that. If it doesn’t work, then it will mean manually adding alt text to about 600 posts.

Exploring the “Analyze” Dashboard

Phostir error distribution

Phostir also provides another way to assess your site data via a color-coded chart that correlates the number of page views with the Phostir quality score. It’s a great way to see how your site stacks up (and as a plus, you can also see which pages visitors are viewing).

Hover over a red dot to find out which pages are registering errors, then click on the link in the pop-up to open your site in a new window and see the errors. Phostir says it will highlight errors on page where possible, but this didn’t work on my site. (Update: Phostir has upgraded the software to highlight errors in source code for pages where the on-page highlight doesn’t work.)

Phostir Error Checking

However, the popup box (called the floating Page Optimizer) showed error links which gave more detail on the errors on the page, so I was still able to access useful information that would help me improve the usability of my site.

Phostir identifies both regular usability errors and accessibility errors, which is useful for those needing to comply with legal guidelines. The explanations for each fix are useful too, as they will help you avoid errors in the future.

Why I Like Phostir

I believe Phostir is way better than a regular mobile testing or conversion optimization tool because it makes it easy to fix your site quickly. You can easily drill down into the data to see if website errors are universal or whether pages desktop and mobile users experience pages differently.

The inclusion of the Phostir tag seems to make no difference at all to page load speed, and in this beta version there’s also no limit on the number of pages it tracks.

The insight into the devices people are using to access your site can help with design and marketing strategy. But Phostir’s killer feature, in my view, is the traffic light ranking of usability errors.

When you consider the huge amount of data available on only two screens, this makes Phostir one of the simplest tools around and definitely worth a try for troubleshooting usability issues.



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Sharon Hurley Hall

Sharon Hurley Hall is a professional writer and blogger. Her career has spanned more than 25 years, including stints as a journalist, academic writer, university lecturer and ghost writer. Connect with Sharon on her website.


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  1. December 11, 2013 at 9:07 am

    Interesting, I’ll definitely be looking into Phostir more. Here are my best usabiliy analysis methods,, hope you like it 🙂

    • Sharon Hurley Hall says:
      December 12, 2013 at 7:05 am

      Thanks, Jessica, I’ll have a look.

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