Budget 2015 visualisations

By Aaron Schiff 26/05/2015

The NZ Herald published some great visualisations of Budget data yesterday. My favourite was Harkanwal Singh’s bubble plot that simply shows percentage changes in expenditure categories.


The really nice thing about this is that the bubbles move and interact with each other. The result is a slightly chaotic but still very legible breakdown of expenditure. I like this because it doesn’t try to do too much — it gives you an overall sense of the 2015 Budget and the changes since the previous Budget, but you don’t get lost in the detail. The physics makes it interesting to explore and every time you get a slightly different visual display but the overall message is the same. And believe me, that bubble physics stuff is hard to do!

Also on the NZ Herald site, Keith Ng made an interactive chart that compares past budget forecasts with actual results. This is a more traditional visualisation in that it uses line charts, and it is a really interesting and useful piece of work. Forecasting is hard to do accurately, but the one thing you really want to avoid is consistently over- or under-estimating.

For example, the unemployment rate forecasts:


In the short term these look not too bad, although it looks like some of the earlier forecasts were too optimistic about the rate at which unemployment would fall. In the long term, all of the forecasts seem to be assuming that unemployment reverts to a long-run average (about 4.5%). This is a common forecasting assumption, which you may or may not agree with. But it shows the value of this exercise by revealing assumptions that are not otherwise obvious.

On the NBR site, Keith also published an interactive treemap that breaks down budget revenue and expenditure into all its glorious detail. One thing I like about this is that it includes the revenue side of things as well, which is often overlooked in all the emphasis on who is getting the money:


Guess what is the second biggest box? NZ Customs. Ok, it’s mostly GST on imports, but still there is $2.3 billion in revenue from customs duties, ie taxes on imported goods.

Addendum: Somehow I missed Chris McDowall’s interesting dot chart breakdown of expenditure:


As Chris says, it’s a work in progress, but I think this is quite a neat way to see where the money goes and what the government’s priorities are.