Here is a graph that purports to be a summary of numbers of divorces per 1000 married people between 2009-2016, i.e. the first part of the graph up to 2014 is before same-sex marriage became legal.
My immediate thought is that this must be wrong—if every marriage is between a man and a woman, then the numbers of divorces must be equal between men and women. So, could the “per 1000 married people” be the gotcha here? Again, no. It doesn’t say “per 1000 people”, but “per thousand married people”, and so in the era that this is referring to, the number of married men and married women would be identical. This suggests that there is an error in the calculation here; oddly, the graph has identical numbers from 2013 onwards; we might expect some divergence if we carry on with the graph, even simply due to statistical fluctuations the number of same-sex male divorces and same-sex female divorces is likely to be different.
So, what is happening during the 2009-2012 part of the graph? I suspected initially that they have mistakenly used “per 1000 people” on those entries in the graph, rather than “per thousand married people”. But, this is at odds with the numbers from 2013-2016, where the graph is as expected—numbers “per thousand people” will be a lot less than “per thousand married people”, and this huge leap isn’t apparent between the figures for 2012 and 2013. So, what explains it?
I’ll restrain myself from ranting about the heinous sin of connecting discrete values with lines.
Here’s another graph (from this Daily Mail article (ugh!)) that seems to be from the same source and shows a similar error: