By adding a new chart and adjusting a few other small details, this slide from PwC could be a home run.
Like it’s Big 4 siblings, PwC is known primarily for its accounting prowess. But not to be forgotten, its consulting and advisory presence is also large and well respected among organizations around the world. With their acquisition of Booz & Company in 2014 (now cleverly named Strategy&), the firm has continued to expand its prominence and prestige and even managed to score the #5 spot in Vault’s 2021 Most Prestigious Consulting Firms.
In this post I’ll be reviewing a slide from a PwC presentation called, “Medical Cost Trend – Behind the Numbers 2017” (source), which is based on a report of the same name. I’ll provide a complete breakdown of the good and the bad, and I’ll try to highlight principles that might apply to any slide building situation.
The slide itself is pretty simple – just a title at the top, and a single column chart. The title says, “Roughly half of employer health costs stem from hospital inpatient and outpatient services; the prescription drug share is small but increasing”. Then the chart shows these different health costs broken down by type – physician costs, inpatient costs, etc. Then it’s further broken down by what share each of these categories accounted for in 2007, and then in 2017, with red boxes showing the percentage change between these two years.
“Medical Cost Trend: Behind the Numbers 2017” PwC
What I like so far is the clarity and descriptive detail in the title. It tells you what they want you to know right up front, that way when I look through the details of the chart I know what to be looking for.
The first part says that inpatient and outpatient services account for about half of employer health costs, which I can see if I take a look at each of those columns – Inpatient accounts for 30%, and outpatient for 19% – for a total of 49%. That’s not something I would have noticed right away or even at all if they hadn’t told me in the title to look for it.
Then the second part of the title tells me that prescription drug share is small but increasing, which you can see in the category “Pharmacy”. It used to account for 14% back in 2007, and by 2017 it accounted for 17%, which represents a 21% increase. So exactly like it says in the title: small but increasing.
The detail in the title is good, but another thing to consider is how well it matches the chart. The main message from the title seems to be about those inpatient and outpatient costs, with the secondary message being about the pharmacy category growth. But if you look at the chart the emphasis is reversed.
This is a clustered column chart, which puts different subcategories next to each other – in this case 2007 and 2017. The effect this has is it emphasizes the differences between those years. And then those differences are highlighted even more with the bright red callouts that show the percentage change.
Notice also how the columns are all some sort of grey, and the only part of the slide that is colorized is this percentage change callout. So they’ve made it very obvious that the change from 2007 to 2017 is what they want you to notice, which of course very much fits with the part of the title that talks about how the prescription drug share is small but growing.
But then what about the other part of the title that’s supposed to be the main emphasis: “Roughly half of employer health costs stem from hospital inpatient and outpatient services.” That’s definitely not something they seem to be emphasizing visually, which means I have to go digging for it a little bit. It’s not that hard to find, but it does require me to locate the right category names on the bottom chart, then look at the percentages at the top of the columns and add them together.
Of course this process is not a big deal. Most people will be able to make these connections themselves in a few seconds, but when you’re designing your slide your number one goal should be to make things as easy as possible for your audience, because they’re going to be trying to process many things at once, while in most cases also trying to listen to what you’re saying. So using visuals to help your audience grasp your main message quickly is key.
One way they could have made their point a little more clear is by drawing attention to the two categories – inpatient and outpatient. For example they could have put a box over them, or added a callout on the actual chart.
But more fundamentally, I think the problem is that this is the wrong chart type for the message. It works great for the second part of the title (prescription drug share is increasing), but it doesn’t do a good job of showing what portion two categories make up of the whole (half of employer health costs stem from hospital inpatient and outpatient services).
Generally speaking, column and bar charts are best for comparing categories against each other. In this case that would mean either comparing 2007 with 2017, which is what they’ve done, or Physician with Inpatient, Outpatient, and the other categories. The reason why these charts are great for this is because you can easily compare the lengths of the bars.
But to show the portion these two categories make up of the whole (to fit with the title), you’re probably better off with a pie chart. And that’s not something you’re going to hear me say very often – in general pie charts are extremely overused, but in this case it makes sense. The reason why is because Pie charts are good for showing the portion of a total (see my rant about Pie Charts here).
In this case you would put all the categories from 2017 in a single pie chart and use a different color to highlight the inpatient and outpatient costs together. This would show very clearly that they make up about half of all employer health costs. The audience hardly has to do any thinking here to understand the message.
The obvious downside here is you can’t really show changes very well from 2007 to 2017. Even with two pie charts side by side it’s not going to be nearly as clear as it is with our clustered column chart. So my recommendation for this slide would actually be to have two charts – the pie chart and the clustered column chart, each emphasizing a different message. Rather than trying to squeeze two very different messages into a single chart, you can isolate each and make the visualizations very clear.
Another criticism I have with the chart and with the slide more generally is the inconsistency of the words. For example, in the title they say “prescription drug” but the chart says “Pharmacy”. In the title they also mentioned “employer health costs”, but in the chart it’s framed as “employer health benefits”. I understand that these are referring to the same thing, but the lack of consistency adds a layer of confusion.
Despite these imperfections however, overall I think it’s a pretty decent slide. The title is strong and the chart could be better but it’s still mostly clear. The use of red is great and really helps highlight the insights, while still keeping the slide professional. By just adding a pie chart and adjusting a few other small details, the slide could really be a home run.