The presidential election...

...is in full swing. Nate Silver, writing in his blog today, reminds us that (my emphasis): 

...there have been only 16 presidential elections since World War II. That simply isn’t a lot of data, and overly specific conclusions from them, like “no recent president has been re-elected with an unemployment rate over 8.0 percent” or “no recent incumbent has lost when he did not face a primary challenge,” are often not very meaningful in practice and will generally not carry much predictive weight. 

I wrote about this in February and will no doubt have to write about it again (and again) between now and November.