It is a political truism that incumbents win with a strong economy and lose in tough times. By this measure, how does Barack Obama fare? The Economist tracked his performance in terms of growth and unemployment for the 18 months before election day, and compared it against all post-war re-election bids.

Looking at GDP (first chart), the latest growth figure, 2.1%, puts Mr Obama much closer to the records of losing candidates, and below their average. Only one incumbent, Dwight Eisenhower in 1956, won with an economy growing more slowly. The situation is even grimmer when it comes to joblessness (second chart). Even at the recently improved rate of 7.8%, Mr Obama faces the worst rate of any incumbent for more than 50 years.

But Mr Obama can take a crumb of comfort, too. Growth may be pretty much flat (though at least not falling, as with past losers), but the unemployment rate has fallen from more than 9% over this period. That is a performance in line with those of incumbents who won.