Two apps for rich, interactive exploration of complex fertility, mortality and population structures in Scotland and comparator populations

Jon Minton, Public Health Intelligence Adviser at Public Health Scotland, has developed two online data visualisation apps which allow fertility rates, mortality rates and population counts in Scotland to be explored by age, time and sex in an interactive and intuitive way. And compared against dozens of other populations from across the world.

The key concept behind the app is the Lexis surface, which is a way of thinking about and visualising fertility / mortality / population data as if it’s a spatial surface.

Just as a spatial surface has height that varies by latitude and longitude, so a Lexis surface has a ‘height’ (a mortality risk, a fertility rate, a count etc) that varies by both age and year. The app turns these Lexis surfaces, each made up of tens of thousands of numbers, into three dimensional computer generated structures that the app user can move around and interact with in various ways.

By clicking on a point on the surface, three additional sub-plots appear below.

  • Bottom left: The way that fertility / mortality / population varies by age, for the year of the point that’s been clicked on.
  • Bottom middle: The way that fertility / mortality / population varies by year, for the age of the point that’s been clicked on.
  • Bottom right: The way that fertility / mortality / population varies by age, for the birth cohort of the point that’s been clicked on.

In effect, these three additional plots show what the surface would look like if you cut either parallel to the age axis, or parallel to year axis, or across a diagonal at 45 degrees to both the age and year axis (i.e. following a birth cohort).

This approach is like cutting through a very lumpy rectangular cake in one of three ways, then showing one of the cuts face on.

Hence, Jon has previously described the apps as making data exploration ‘a piece of cake’!

The two apps profiled on this page are as follows:

For further information, please contact jon.minton@phs.scot.