The latest version of the GBD is both bigger and better. For one thing it includes more than a billion pieces of information covering 291 causes of injury, disease, and death, for 187 countries, measured in 1990, 2000 and 2010 (published in a traditional form in a series of studies in the Lancet in December).
More radically, the team (now overseen by the IHME, which Murray founded in 2007 and still heads) has now made the information accessible to a wider audience by presenting it in visually engaging ways on an interactive website. Launched in March, their visualisation tool shows causes of disease, injury and death within a rectangular pie chart made up of blocks whose sizes are proportional to the numbers they represent.
Categories are highlighted in different coloured blocks, which are sub-divided into specific causes in different shades, according to whether they are on the increase or decrease. Red signifies communicable diseases, such as malaria or diarrhoea, as well as maternal, neo-natal and nutritional disorders. Blue is for non-communicable diseases, including cancer, heart disease, and diabetes, while injuries are represented in green.
Users can select the entire developing world, for example, and pull the lever from 1990 to 2010 to see that communicable diseases overall have decreased as a percentage of mortality. They can view metrics across the whole world, regions or individual countries, focus in on specific time frames and ages, or look at outcomes for men or women only. Other visualisations allow comparisons and rankings of causes of death, disease and injury in different countries.
Projects on this scale have only recently become possible thanks to the enormous increase in data, greater computing power, and new ways of doing statistical analyses, according to Peter Speyer, data director at IMHE. "The technology was not advanced enough even five years ago to have an easy way to visualise all this data," he says.
The initial spark of inspiration came in the autumn of 2010 when Kyle Foreman, then working as a research fellow at the IMHE as part of his Masters degree in public health at the University of Washington, got fed up with boring charts. Foreman taught himself D3, the program the team still uses to create the visualisation, and made a prototype for internal use.
“It didn’t take long before we realised just how powerful these tools are,” says Murray. “That’s when we realised that we needed to invest in doing this in a way that everyone could use.”
The effort to collect and interpret the data was immense. Speyer says that in addition to the nearly 500 official authors from 50 countries, the IMHE worked with thousands of organisations around the world to access the data.
Despite that, it’s not perfect. The results are only as good as the data collected on the ground, and Murray has heard occasional criticisms. “There are always people saying, ‘No, you haven’t done a fair job for blindness, or you haven’t got cholesterol right in Indonesia because you missed my favorite study’,” he says.
That’s an easy fix, he says. If and when new data becomes available, his team can integrate it. There are also plans for more general updates at least once a year. Some problems, however, can’t be solved by larger data sets. For instance, some scientists claim that malaria is over-diagnosed in hospital deaths in Africa. “That’s a tough one to deal with," adds Murray. "You have all the data on one side and expert opinions on the other. The bottom line is, we won’t really know until more studies are done.”