Europe was racked by two world wars in the last century, both of which created near-famine conditions. Presumably, this caused Euro-heights to lag that of Americans, an effect that probably skews data until we get to Europeans born after, say, 1955. In other words, when Paul Krugman saw eye-to-eye with Europeans in the early 1970’s, he was looking at a lot of war-deprived shorties.
However, regardless of the absolute wealth of Europe versus the United States, from about 1955 onwards (or, in terms of measuring adults, form about 1975 onwards), one would expect Europe to increase more quickly than the US, simply because they are moving up from a war-depressed baseline.
Second problem – what is the ethnic mix of Europe relative to the United States? I would hazard a guess that healthy, well-fed Swedes are taller than healthy, well-fed Irish or Italians. The United States has descendants from all three countries, but I would hardly be surprised to learn that Sweden has surpassed the US in height. But are the Irish in Ireland taller than their US counterparts? Are the Scandinavians in this country lagging the Scandinavians who stayed behind? Who knows?
And an alternative explanation – rather than blaming America’s work ethic, let’s idly speculate that the cause is the general European welfare state.
The humor here is that Krugman shows such a persistent tendancy to disregard rigorous norms in statistical analysis, with Krugman being an economist by training.
Did they ever consider that 20 million+ Mexicans, Chinese, etc., that have moved here in recent decades, are dragging down the average height of Americans?
Anyhow, while there are many problems caused by uncontrolled immigration (which seems to be the favored policy of leaders of both political parties), I don’t see why we need to worry about our height.