Affordances and Signifiers: applying design theory to your dashboards

When designing objects, be they hotel room taps/faucets, iPhones, or cars, the creators grapple with the concepts of affordances and signifiers. These terms were introduced into design by Don Norman, author of The Design of Everyday Things, based on earlier work by JJ Gibson.

What are these and how can we apply them to our dashboard design?

  • An affordance is something an object (or dashboard) can do. A tap/faucet can run hot or cold water, for example.
  • A signifier is an indicator of some sort. In our tap example, this might be red/blue dots signifying which way to turn the tap to get hot or cold water.

How many times have you tried to use a tap in a bathroom and not known which way to turn it for hot or cold? This is a frustration of modern life: apparently a sleek design is more important than signifying (red/blue) the affordance (hot/cold).

Dashboards have affordances and signifiers. How you implement them will influence their success. Let’s use an example. I’m going to use an excellent dashboard by Eric Brown. It allows you to compare gestation periods of different animals.

Let’s play a game. Here are the rules: take a look at Eric’s dashboard and, without using your mouse, identify all the ways in which you can interact with the dashboard?

Click here for the interactive version. Creidt: Eric Brown

How many did you count?

There are eight intentional affordances Eric built into this dashboard. Did you spot them all?

How many of those eight affordances have a signifier?

Here are the affordances:

8 affordances (there are further affordances in the tooltips)
  • 1, 5 and 6 are drop down filters. Drop-downs are a staple of interacting with dashboards, and web pages. But why put the three filters in different places?
  • 2, the light bulb, is a hover-help tooltip. Hover over the light bulb and you see a description explaining how the compatibility score is calculated. That’s great if you’re familiar with the “hover-for-help” trope, but if you’re not, then, well, it’s just a light-bulb. How would you know it contains an explanation?
  • 3 and 4 allow you to click on the animal to highlight it in the scatterplot and see more details.
  • 7 is the colour legend. If you click on one of the colours, it highlights all animals in the scatterplot in that category. Does the dashboard tell you you can click on the legend?
  • 8 allows you to click and see the datasources.
  • Note – did some of y ou think you could click on the silhouettes of the whales in the top right? If you’re a Tableau expert, you might have thought you could. But, no, that is just a legend. It has no interactivity.

That’s a lot of stuff you can do with this dashboard. But only some have signifiers.

We could solve the problem by ensuring every affordance has a signifier. Here’s what that could look like:

All the affordances!

Here are the main changes I made:

  1. Move all drop-down filters into one place
  2. Added instructional text to the scatterplot and colour legend
  3. Removed the hover-help tooltip and placed the calculation explanation in the bottom right, above the data source links

I could now claim to have fixed the “problems” with Eric’s dashboard. Anyone now coming to the dashboard with no prior training in it, or dashboards in general, now has a signifier for every affordance. If they invest the time in reading the dashboard, they will be able to interact fully.

Should I always create a visible signifier for every affordance?

No. Sometimes you are designing dashboards for an internal audience. They may be familiar with dashboard interaction, or you can train them. In which case you could remove the signifiers.

The thing you need to do when designing a dashboard is consider your audience, and how you can communicate to them that they can interact with the dashboard. Skilled users know to click and experiment, or can be trained to do so. New users don’t have that knowledge or confidence. Your job is to make these decisions consciously, not by accident.

Although this example isn’t in my upcoming book, The Big Book of Dashboards is pakced full of successful dashboard designs and tips. Sign up for details here.

Note: Eric’s dashboard is excellent, it looks super and is a pleasure to explore. He’s graciously given me permission to use in this post, and I thank him for that. 

Changing the message without changing the data

Two formats, two messages. Time for a new example?

If you’ve seen me present in the last 3 years, you’ll probably have seen me show the Iraq Bloody Toll chart. Then you’ve seen me turn it upside down to create an entirely different message (full post here).

I still love showing this example to new audiences. I love seeing the light bulb go off as they realise that a data and a chart is just a method of communicating a message: facts are not neutral.

But it’s time to find a new example and for that I turn to you for help.

Have you got any other great examples of charts where the message can be transformed in as simple a way as this one? 

(Note: I’m only looking for examples that stay true to good practice. Truncating the y-axis doesn’t count!)

There are some older examples. Obama’s bikini chart was a cracker, described very well by Robert Kosara in 2012.

Do you know any others? If I can find enough, we could turn this into an entire blog post or webinar. Let me know in the comments or on Twitter.

Is Trump signing more executive orders than anyone else?

[UPDATE: I will be delving into my motivation for building this viz, and how I did it, in a #MyRecentViz webinar on Feb 7th]

Click to see an interactive version

As a left-leaning citizen, I watch in horror as Donald Trump dismantles Obama’s legacy. As a British person, the reports of Trump’s signing of a multitude of executive orders, actions, and presidential memoranda leave me in shock. How can a nation have a system where a president can pass laws without any checks or balances?

“Surely this level of activity is unprecedented,” I think.

Wary that drawing a conclusion based on media reports alone is risky, I sought the data to compare Trump to previous presidents. I got the data from the excellent American Presidency Project.

My data-driven, fact-based conclusion is disheartening: Trump is merely following the lead set by Obama 8 years ago. Barak Obama signed 9 executive orders in his first 10 days. He was the first president to get the pen out to dismantle the previous president’s legacy. Prior to Obama, George W signed two orders in the first ten days. Before him Clinton signed three.

8 years ago, I probably applauded those executive orders Obama signed. Little could I predict that he was setting a precedent that could be used by any future president.

For more on executive orders, Jurist has a good summary. has a good summary of the difference between executive orders and actions.

MakeoverMonday: the price of your Christmas dinner

This is it! The FINAL MakeoverMonday of 2016. What a year it’s been. Thank you to everyone for making this project something exceptional.

Anyway – here’s my makeover. The light of the christmas star shines upon my data this week:


If you celebrated Christmas yesterday, I hope you enjoyed the food. Did you consider how the price of all those parts of it have changed over time? I hadn’t, and the dataset was fun to explore.

Here’s a secret, I really wanted to make the one below my “official” entry to this week:


I love the way it looks like rays of light shining down. Unfortunately, I couldn’t bring myself to make this the “official” one because when the slope lines are pointing down, you just can’t label the lines, which leaves you with a pretty viz but one without insight.

How did I get to this? This was one of the quickets Makeovers I did. Line chart, slope chart, % difference and then the idea for the star:


I’m full of turkey, and goodwill, so this week, I’m not doing any commentary on the original from the BBC.

Next week is a new year. We’re going to stop recording stats and updating the Pinterest board, but MakeoverMonday will continue with new datasets each week.

MakeoverMonday: DC Metro Scorecard

I had one goal this week: could I show all the measures in the space the orginal scorecard shows two?


The answer? Yes, and not just by using 6pt fonts!

Bullets are an easy way to see actual against a target, and they take up way less space than curvy bar charts. Missed targets are encoded twice: the bar is below the target reference line and the label is red.

One thing I don’t like about my approach is the arbitrary axis lengths. Some of the metrics are percentages, so you can set the axis range from 0-100%. That way the viewer can see three things:

  1. The actual value
  2. The distance from the target value
  3. How close actual/target are from perfection.

Where the metrics are values, how should you set the axis range? Look at the charts on the right hand side. They are all very different scales. Should I let the chart tool set the range automatically? If I do that, the bar or reference line will be right at the right hand edge of the view. Or should I artificially extend the axis, creating a nicer sense of white space?

The original

There’s lots to like about the original:

  1. There’s a thumbs up/thumbs down for good/bad performance. That makes it easy to identify which metrics are being met.
  2. The actual value is labelled in the centre of the circle.
  3. The targets are defined in text

The main thing to dislike is the curvy bars. They don’t add anything, other than a sense of colour and false excitement. Really, to fix this scorecard, all they’d need to do would be to flatten out the bars and shrink the layout.

[Note: the original was updated to fix an error in the color encoding of my makeover. Thanks to Clibo for pointing it out.]


MakeoverMonday: Safe States to Drive


This week’s original focusses on the worst states to drive in. It’s nearly Christmas so I wanted to turn that around and take a more positive approach: which state is the best. Turns out it’s Minnesota.

My makeover removes almost all detail (ie 49 out of 50 states!) but I decided after exploring the different metrics to focus on a single message: stay safe, rather than let people investigate the data in each state.

You can see that process in the GIF showing my exploration, below. I looked for correlations and patterns, but once I hit the map, I realised I wanted to focus on Minnesota, and spent about half my time getting the display just so.

Exploration followed by formatting
Exploration followed by formatting

The original

There are things to like in this week’s original:

  1. The colour bands are groups rather than every individual rank. It’s easier to identify a colour band representing 1-10 rather than trying to find the one ranked 6, for example.
  2. Maps make it relatively easy to find your state.
  3. They’ve labelled which is best and worst. Should 1 be “worst” state or “best”? They made a decision and labelled the legend.
  4. The small states have their own callout rectangles.

What don’t I like?

  1. I didn’t notice the “Next” button until writing up this blog. Turns out there are 3 charts, but I didn’t notice them.
  2. Choropleths distort values because one value covers large areas.

What has MakeoverMonday meant for you?

A selection of mine and Andy’s makeovers. Click for a much bigger version.

The 2016 MakeoverMonday project is coming to an end.*

How was it for you?

I want to know what your favourite week was, and why. What have you learnt? What have been your highlights (and lowlights)? What’s the effect been on your community? And the wider dataviz community?

I’ll be writing a post on before Christmas so please share you reflections with me, in the comments, on Twitter, on your blogs, or anywhere else I’ll see them!

* What does “coming to an end” mean? Andy will continue to add datasets each week. However, as of the end of the year, we will cease to update the Pinterest board and the dashboard of statistics. We hope you all still continue!

AskAndy anything: resources

Andy Kirk and I did the 2016 #AskAndy anything webinar today. We hope you enjoyed it. Let us know your thoughts on Twitter using #AskAndy. This post contains the slides and links to the resources we shared.

What to buy a data geek for Christmas?

Possibly the most important question was one Andy Kirk asked: have you done your Christmas shopping yet? If not, you might want to check out the eagereyes holiday shopping guide.

Principles and Purpose of Dataviz


The original: click here for the interactive

Chart Types and Techniques

Personal Development and Skills

The State of the Nation

MakeoverMonday: Global Flow of People

Click here for the interactive version
Click here for the interactive version.

I went super simple this week: all you can do in my viz is select a country and see where people went to. You can only see one origin country and I only exposed the most recent year.

The original chord diagram lets you see a very large amount of the dataset simultaneously.

The original: click here for the interactive
The original: click here for the interactive.

I used to dislike chord diagrams: too complex. really messy, incomprehensible. But then this chord diagram was presented at Graphical Web in 2014, and it changed my mind. Why?

  1. The designers took the time to explain how the chord diagram worked. Once you have worked out the mechanisms, the data pops out and becomes clear. Taking the time to read the instructions and learn how to read a chord diagram is time worth investing
  2. Chord diagrams require interactivity, and that’s fine. The initial state is an overhelming confusion of lines. Interacting brings it to life. Charts that require interactivity can still be valid.
  3. I do not believe there is another way to visualise flow that has so much detail. My own makeover this week is an admission of that: I’m using filters to show only a part of the data. Andy’s own makeover is a massive simplification of the dataset. It’s fine, as a matrix, but comes at the expense of detail, which the chord does contain. Almost all of this week’s makeovers show only a slice of the full data. Only the chord diagram allows you to access it all with ease.
  4. People shouldn’t shy away from complex charts. Chord diagams do not provide instant insight: you need to invest time to read it. That is not a reason to shy away from a chart. Alan Smith discussed this on the PolicyViz podcast: he explained why they used a chord diagram in the FT this summer, knowing it was a chart that needed time to digest. That’s well worth a listen.
  5. Chord diagrams cope with a range within your measures. Some countries have really huge numbers of people moving, while others have tiny. The outliers dwarf everything else when you encode with colour or length. I think width is a more successful encoding in this case.

I love the original chart. It’s visually striking, it’s engaging and there is a vast amount of detail available in one view, once you’ve devoted the time to learn how it works.

MakeoverMonday: Inequality in the US

This week provided a good challenge. It’s difficult to present data which divides one percentage (US Wealth) into categories about another percentage (household income).

My first try is with an Area chart. I like the area chart because it shows part-to-whole for the entirety of US Wealth:



But it doesn’t quite punch home the differential between bottom 90 and top 0.5. Could I do that another way?

I chose to drop the history and focus on just the most recent year.

How about a stacked bar?


Or a bar chart?



They’re ok but the fundamental problem is that this approach doesn’t capture the size of “Bottom 90%”. The words “Bottom 90” don’t capture that magnitude of the inequality.

To tell this story in the most powerful way, I think we’d need a way to encode the 90%/0.5% households, too. And rather than spend time making that viz, I’ll share this video instead. It does one of the best jobs of showing the extent of inequality I’ve ever seen:

This week’s original had some annoying design choices.

What I liked:

  1. The legend was clear
  2. Everything that needs to be labelled is: axes, data sources, etc

What I didn’t like:

  1. The tick mark interval on the x-axis. 1917, 1927? Make it 1920, 1930, etc
  2. No need for the dual axis labels
  3. Lots of fonts
  4. Nothing is aligned or spaced out nicely. It’s all cluttered and creates an amateurish look.