I am improving a risk diagram. It seems difficult to place the axis labels.

Here is the current situation:

Diagram in original form

My customers and I are not happy with this. Customers suggest to have the axis labels vertically and horizontally. This is where I don't find a better solution. Having the labels near the diagram seems to rip the relation between the value label and the picture. Also, the meaning of "vertically aligned font" and "horizontally aligned font" are mixing up.

Diagram with axis labels near

If I take the axis labels outside, then they are some strangeres far away, my eye is not relating them to the color field:

Diagram with axis labels far

What further options are there in designing such a diagram?

  • 1
    are there any potential values that go in the cells, or is color the sole indicator? Also, what are the numbers doing in the labels, are they something indicated elsewhere?
    – Mike M
    Mar 17 '19 at 15:40
  • @MikeM, in the cells are bubbles, i.e. circles with gradient and border, and small labels. The numbers are often used in the software at other places, they act as signals. Mar 18 '19 at 6:03
  • I assume that this is meant to be a 'print' rather than 'digital' diagram and therefore no interaction design allowed?
    – Michael Lai
    Mar 18 '19 at 23:19
  • @MichaelLai, right now this diagram is in fact used to have some interaction. A click in the colorful matrix is setting a marker for the current risk, so it's a handy risk evaluation. Clicking the axis shows further information in a modal dialog, that helps to be precise and to reason the evaluation. Mar 19 '19 at 7:12
  • If it is interactive then why not allow the user to hover over the values in the axes and show the corresponding description? That would be one solution for the problem of the awkward alignment of text.
    – Michael Lai
    Mar 19 '19 at 21:18

Try using visual alignment, and have the title read like a sentence. You can try some tradeoffs on the axis labels (truncation and word choices).

I don't know your use case and some constraints, but if you have some flexibility, you can give more clarity to the diagram by a combination of more explicit labels, and truncation where necessary.

Axis labels and readability

Here you have an opportunity to both declare the purpose of the diagram, and use visual alignment, nomenclature and position to tie everything together.

Rather than have users tilt their head and readjust to view the axis labels, put it on top as a sentence:

enter image description here

The yAxis:

In this case, you can use alignment of the title, and repeat the term 'probability' in the top and bottom label to match the heading above it.

I replaced small with low, as we associate things going from low to high, rather than small to high, i.e. 'there's a low probability of x occuring'.

The xAxis:

Now you have the title just above the labels. You might need to make a tradeoff here in terms of truncation. I'm not sure how much flexibility you have in terms, but rather than repeat the term 'small' for both axis, I used small, med, large to show progression.

enter image description here Depending on the size of your labels, you might be able to spell out Small, Medium and Large, leaving only the first truncated.

  • You are showing me some valuable approaches that help me to get out of the box. Thank you. I will probably use full labels and numbers too, however from here I can deal with them. Mar 18 '19 at 6:13

I think there are more ways of differentiating information fields using the same orientation in the titles:







  • Your suggestions are helping to guide the eye and to avoid that labels and their relations are ripped apart. This is helpful, thank you. Mar 18 '19 at 6:24
  • 1
    +1 This is an elegant solution/suggestion to the problem using basic gestalt design principles!
    – Michael Lai
    Mar 18 '19 at 23:17

The British Met Office get round this by integrating the axis legends into the labels themselves, and it's less 'ink' too



Of course, that doesn't tackle the issue in these matrices that a small chance of something really bad happening gets given the same representation as a large chance of something quite benign happening, but I guess that's another issue :-)

  • Thank you for this valuable hint. While this is helpful for seeing easier, it is against my use case. In my use case, the risk diagram is used to discuss together in detail things like, "why is the risk to be set at damage level 3 but not damage level 2". Therefore, the detailed infos should not be dropped. I did not mention this in the OP though. Mar 19 '19 at 7:50
  • You could easily add numbers, it's the labels that take up all the space. If you want to muddy the waters further, assigning labels such as 'moderate' and 'greater' is going to cause issues, as different people will interpret the same term differently and as being separated by varying semantic 'distances' - basically not necessarily uniformly separated like a numerical scale. It's a known issue in questionnaire design at least - see stats.stackexchange.com/questions/10/…
    – mgraham
    Mar 19 '19 at 9:54
  • You are right, there is a lot of semantic blur in such discussions. I will study your link. Our approach so far has been to offer detailed information in dimensions to have guiding criteria. E.g. the financial damage may be unclear, however the legal damage is a long court case, therefore it's damage level 3. And so on. But it's worth to discuss to have this information, and also the very most labels, outside. Michael Lai proposed this in his answer. Thank you so far for sharing your thoughts. Mar 19 '19 at 10:48

enter image description here

This is my proposed solution (except for the title of the diagram), with a few key points highlighted:

  • I think it is important to also provide values for the risk categories which appears to be missing
  • I think a legend/table providing detailed descriptions is better than cluttering it around the axis, although you still need to provide values to help with pinpointing the risk value on the matrix
  • I also think a legend/table will provide more flexibility if the text is too long or descriptions need to be changed in the future
  • I think that a legend/table makes reading much easier
  • I think it is not necessary to provide descriptions on axes because it is information that becomes unnecessary to display once you are familiar with the diagram so it doesn't need to included in the main diagram.
  • this kind of separating the information is promising. Thank you for your help. Mar 20 '19 at 8:48

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