How I did that: Stroke infographics
|Mortality||Who’s affected?||Care and costs||Risk factors|
As part of our Focus on Stroke we produced four in-depth infographics to make sense of the various issues surrounding stroke. But with so many statistics available, making sense of them was a major challenge. Our Information Designer Paulo Estriga talks us through the process.
My starting point was Stroke Statistics 2009 Edition, an exhaustive 108-page report published by the British Heart Foundation. My brief was very open: essentially to examine it and see how we might interpret these visually for a wider audience.
The first step was to thoroughly analyse the document looking for stories that could be told with the data. I identified four. The first was stroke mortality in the UK: from the absolute numbers we would establish the seriousness of the situation by comparing them horizontally to the mortality of other diseases, and vertically to stroke mortality in past years. For the second story we would look inside the numbers and find how they broke down, how they showed some people were at a higher risk than others due to geographic, ethnic and socio-economic reasons. The third would look at what treatment and care there is if you have a stroke; medication, hospital and residential care and how much this costs the National Health Service. Finally we’d look at risk factors and what you can do to reduce your risk.
This order may seem counterintuitive, as somehow it’s the opposite of the real order of events (i.e. bad health habits lead to a stroke, then to care and eventually death). But showing them in this reverse order allowed us to start on the negative, understand the problem and end on a positive note, leaving with useful advice and a call to action — something useful readers could use to improve health habits. The aim of this work wasn’t just to inform, but also to provoke change from that awareness.
After researching what interesting patterns and relationships in the data would best help tell the stories, I researched the visual style to be used and the appropriate charts for the different types of data. There was enough richness in the data to allow the charts to do the ‘visual talking’, with no need to add a lot of illustrations to make it more interesting. And the subject at hand didn’t warrant much playfulness, so a clean, sober, clinical style would be appropriate.
I started laying out the basic structure with the relevant graphics using data from the report, leaving some space for complimentary text and pontificating the infographics with ‘fast facts’ — big important numbers I found striking during my analysis. I tried to use appropriate chart types for the data they would represent, while at the same time keeping it varied to stimulate curiosity and discovery in the reader.
Although packing more information into each graphic can tell a more complete story, I tried not to overwhelm the reader and instead looked to distribute some of the information in different graphics or between graphics and text so that it could be grasped in a more balanced way. I also tried to maintain the level of detail and rate of information somewhat even throughout each and across the four infographics, avoiding too weak or too complex spots that would put the reader off. This led to the sacrifice of a couple of charts that, although very informative, had too many variables, requiring too much effort from the reader to interpret them.
Once the structure was laid out, it was time to draw the graphics using the most recent numbers possible. This required some graft. The fact that the UK comprises several countries and not just one makes this work significantly lengthier as there are independent statistics departments for England and Wales, Scotland and Northern Ireland. Never underestimate the amount of research, calling and chasing required to get the numbers you need! From the start, we’d been in touch with the researchers behind the original Stroke Statistics 2009 report and the Office of National Statistics. We also spent a significant amount of time trawling the web for other reliable sources. Our colleagues at The Stroke Association were invaluable in interpreting this minefield of information and pointing us to the right places to start.
For some statistics we just couldn’t find enough recent data, so some graphics had to be dropped so as not to mislead the reader with old statistics.
Another problem was that the numbers often came in formats that were not appropriate for the charts intended, for example, absolute totals where we needed relative percentages, or the rate for men and women separately when we really wanted an average. All this conversion work needed to be double and triple-checked to ensure no wrong information would be conveyed. Any numbers that didn’t ring true also had to be checked and challenged before they could be used.
I always try to convey data in a way that is relatable to the reader, both visually and in the text. It’s important that the reader can relate the information to his or her own life, family, ethnicity, socioeconomic condition or habits, and not just see a bunch of abstract numbers. This is an especially difficult challenge when dealing with enormous numbers or something as abstract as a percentage or ‘Age-standardised mortality rates per 100 000 of the European population’! Rates, for instance, are calculated through a very inaccessible formula, so I try to convey these visually using proportions. In the accompanying text, I made other numbers more understandable by using terms like “a third” or “3 out of 5” instead of percentages, or, if possible, reducing yearly totals to the smaller daily average, which ends up feeling more personal and impactful.
The last of the four infographics, on risk, presented an unexpected problem. Since the information we have on risk factors is taken from different studies made in different conditions and provided results measured in different units, it was impossible to consistently create charts establishing relationships or patterns across risk factors in, for example, the same ethnicity or socioeconomic condition. Because of this we decided to simply list the risk factors with a few quick facts and focus on advice on simple lifestyle changes that could directly and significantly reduce a person’s risk of having a stroke.
Again, accuracy was foremost in our minds, so we were careful to list all our sources and double and triple-check our text and graphs with our colleagues at the Stroke Association.
We published the infographics one a week during May and they proved a big hit. The Guardian republished them and The Stroke Association are looking to repurpose them as handouts for patients. One of the biggest pleasures of infographic design is making complex, hard to grasp data understandable and enjoyable. I hope we’ve achieved that with these.
Paulo Estriga is a freelance designer.