A lot of people are racking their brains trying to explain some wrong numbers that two Harvard School of Public Health researchers graphed. The real explanation of the surprising result is that the authors got their crosstabs backwards. They were looking for these numbers (the ones circled in green), which show the percentage of self-identified strong Democrats who say they are in poor health (9.1%), and the percentage of self-identified strong Republicans say they are in poor health (5.0%).

FixedTabSplit

Unfortunately, they graphed these numbers (the ones circled in red) which represent something else:

WrongTabSplit

Among many other places, the wrong results (which contained several other wrong numbers caused by the same mistake) were reported here, here, and here, except that it was reported as surprising research, not wrong research. These reports have generated lively discussions about why Democrats are in such poor health. Except they aren’t. With luck, many of the people reading about this will eventually find the answer here.