National, Statastics and (net) Migration

One of the messages that the National Party are pushing this election is to do with the decrease in net migration to Australia. They have been talking it up for a while. One of the ways they have been doing this is producing infographics to show the improvement as new figures are released. There are two graphics I want to talk about:


First the good things, I like the fact that with this series of graphics they are using the same layout and style, which helps to link them all together. I also think it is good that they are using the same scale. Which helps people compare the graphics from month to month. But there is one element of this that has changed. In the graphic with the April figures specifically mentions that they are using the NET migration figure, whereas in the July figures they have not identified this. But it appears they are still using the net figures.



Now this may not sound like a big issue, but it results in completely different figures. Gross migration is the total number of people leaving or arriving, where as Net is the difference between those arriving and those leaving. The fact that the graphic has not noted that they are using Net figures, as opposed to Gross figures has resulted in a number of negative comments on the Facebook post.




Now I double checked the link that James Peacock posted, which is the one referenced in the graphic. The relevant section of the page reads:


So it is clear from this that the Net migration to Australia was 100 which corresponds with the figures used in the graphic. So are the figures that the graphic uses from 2008 Net as well? Stats NZ still have the figures online, so I had a look:


2700 matches, roughly, with the figures used for July 2008. So it is obvious that the numbers being used in both of the elements are the Net migration figures. They have cited the source of the figures, but in this case the figures contain both Gross and Net figures. However, since this isn’t made clear on the graphic itself, like it is on the April figures, the party has brought a number of negative comments upon itself that it didn’t need too.