Mekko charts can be a great way to answer multiple questions with a single visualization. But they should be used with caution, because sometimes they just complicate the message.
In this post, I’ll explain what a Mekko chart is, when you should use them, and what tricks you can use to make sure yours are clear and insightful. Plus I’ll show you a couple of “real world” examples from McKinsey and explain why they’re so effective.
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Overview
Strategy Consulting firms love to use Mekko charts in their slides. And there is a good reason for this – Mekko charts can be a great way to answer multiple questions with a single visualization. Especially for data-heavy presentations like what you might find in a consulting, strategy, or finance environment.
For example, this chart from McKinsey shows global payments revenue broken down by region and then by revenue type, which is further categorized into commercial and consumer revenue. The downside to Mekko charts however, is that they can be difficult to understand and even more challenging to use correctly.
“Global payments 2021: Transformation amid turbulent undercurrents” McKinsey, October 2021
Start with a column chart
To understand how a Mekko chart works, let’s start with a basic column chart. As we all know, column charts allow us to see data across a set of categories. In this column chart we have a breakdown of home furniture sales by brand: Posh with 88 million in revenue, Ben Smith with 64 million, and so on.
A chart like this is great for quickly comparing the totals of each category. For example, if you’d like to emphasize the message that Posh has the highest revenue, this is the chart for you.
You could also show data in a stacked column chart, which would allow you to use an additional layer: revenue by region. It would not be good for comparing the different regions across companies (e.g. Sales in North for Spencers vs. Sales in North for Rhoog), but it does provide additional context to the data. For example, despite being the second-highest in revenue, the Ben Smith brand does relatively poorly in the North region, bringing in only 6 million in revenue.
A variation on this chart would be a 100% stacked column chart, where instead of displaying the value for each region, it is represented as a percentage of the total. For example, with Import One, 7% of sales come from the West. In the chart, the emphasis is on how the breakdown of revenue compares across brands. What you lose with the chart, though, is the ability to compare the totals with each other. Each column is the same height, so it does not visually show us how much revenue each company generated.
Add another variable
So this is where the Mekko chart comes in. A Mekko chart let’s you use the width of the columns to bring in an additional variable. In this example the width of the columns represents the total amount of revenue for each company.
As the widest column Posh has the greatest amount of total revenue at 88 million. Likewise Rhoog has the narrowest column, and also the least amount of revenue at 30 million.
In addition to this you can still see a percentage breakdown of that revenue by region. Posh has total revenue of 88M, and 20% of that revenue came from the East region.
What’s more, each of the rectangles is now proportional to how much revenue they represent. In other words, everything provides value, whereas before, it was only the height that mattered. I could also change the data labels to show the revenue of each region instead of just the percentage total for that company.
The power of a Mekko Chart
And here’s where the real power of a Mekko chart comes into play. The total revenue for each of these companies combined is about 287 million. If I take any one company, let’s say Posh for example, it will take up space in proportion to the total size of the chart. They did 88 million in revenue, about 31% of the total revenue. And visually, Posh makes up about 31% of the chart.
Likewise, if you take any one section you can do the same thing. Spencers did 24M in revenue in the East region, which is why that section makes up about 8% of the chart… Or about 39% of the area for Spencers only.
Having this kind of visualization can be really valuable when you’re trying to get a quick glance at the size and breakdown of a market.
McKinsey example
Here’s a great example from McKinsey that really shows the value of a Mekko chart. It shows the total amount of global payments revenue, broken down by region, and also by payment type.
And the values in each box represent the percentage of payment revenue for that region. So for example, 5% of payments revenue in Latin America came from commercial cross-border transactions.
“Global payments 2021: Transformation amid turbulent undercurrents” McKinsey, October 2021
Looking at the chart, I can quickly understand how the market breaks down. Asia-Pacific makes up a good portion of global revenue, which is reflected in the title. I can also see that commercial account-related liquidity is the largest source of revenue for Asia-Pacific and the largest source of payment revenue across the globe. And then I can also see that consumer credit cards in North America are a large chunk of revenue as well, especially compared with other sources of revenue in that region.
McKinsey also took it a step further to classify into Commercial and Consumer revenue sources by color-coding into hues of grey on the top and blue on the bottom. The result is a nice-looking chart with clear insights and a simple takeaway.
Mekko Chart criticisms
The Mekko chart is not without criticism. For one thing, it’s not easy to compare the size of each of the different categories against each other. For example, in our original chart, it is hard to tell which group is bigger visually – Posh’s sales in the East or Import One’s sales in the North. For these types of precise comparisons, you are much better off with a column or a bar chart.
Another criticism is that they can be challenging to read – especially for anyone unfamiliar with them. The goal of your slide should be to make it as easy as possible for your audience to understand the key insights, and if they are hung up on the chart, that is not easy to do.
However, despite its flaws, the humble Mekko chart can be pretty powerful in the right situation.
Bar Mekko Charts
Another type of Mekko chart is the Bar Mekko Chart, where the height of the columns is a measure of units rather than a percentage. In a regular Mekko Chart, each of the columns is the same height, but in a Bar Mekko Chart, the height of each column is different.
To illustrate this, let’s take a look at our original chart.
Here the height of the columns represents revenue. But let’s say we wanted to introduce another variable: the number of stores for each brand, as represented by the width of each column.
This still shows me revenue for each brand, but now I have more context for those numbers. I know for example that Ben Smith is bringing in a lot of revenue with only 12 stores. The focus is still on the height of the columns, because that’s what’s easiest to compare, but the width provides additional context.
I also could make these stacked columns to show revenue by region again. However, generally speaking, Mekko charts tend to be confusing because there are just too many visual components to process at once. It’s best to keep it simple by focusing on a single variable, with only a second variable to provide the supporting context.
McKinsey example #2
Another example from McKinsey illustrates the concept well, albeit slightly different. It shows the level of cybersecurity maturity of different survey respondents.
“Organizational cyber maturity: A survey of industries” McKinsey, August 2021
The black column, for example, represents the top 10% of organizations in the sample, a group that’s nearly at level 3 in terms of maturity. Then the next group represents 20% and is less developed, and the final group is the remaining 70% with the lowest level of maturity. But instead of just grouping these into three different columns of equal width like what you might do in a standard column chart, they have let the width represent the percentage of organizations in the survey. So looking at the chart, I see how each group scored.
A few helpful tips
When using a Mekko chart, there are a few essential things you will want to keep in mind.
First, make sure everything on the chart is clearly labeled. It should be clear to your audience what each axis represents. It is especially important for Bar Mekko charts, where the width of the columns might not be evident at first glance.
The second tip is to include outlines for each rectangle, to make it easy to differentiate between the different values.
Third, add additional information to your chart that might help the audience understand your message. It can be arrows, text, or even lines, as in the case of this line that shows the average revenue for the industry.
Then lastly, don’t use a Mekko chart unless it makes things easier for your audience.
It can be helpful in the right circumstances, like when you need to understand the data quickly and direct comparisons are not as meaningful. Or, in the case of the Bar Mekko chart, when you only need to compare a single variable, but adding an additional variable can provide important context. Otherwise, you’re probably better off with a simple column or bar chart.