Suppose that for some reason you decided to start hitting yourself in the head, repeatedly, with a baseball bat. You’d feel pretty bad. Correspondingly, you’d probably feel a lot better if and when you finally stopped. What would that improvement in your condition tell you?

It certainly wouldn’t imply that hitting yourself in the head was a good idea. It would, however, be an indication that the pain you were experiencing wasn’t a reflection of anything fundamentally wrong with your health. Your head wasn’t hurting because you were sick; it was hurting because you kept hitting it with that baseball bat.

And now you understand the basics of what has been happening to several major economies, including the United States, over the past few years. In fact, you understand these basics better than many politicians and commentators.

Let’s start with a tale from overseas: austerity policy in Britain. As you may know, back in 2010 Britain’s newly installed Conservative government declared that a sharp reduction in budget deficits was needed to keep Britain from turning into Greece. Over the next two years growth in the British economy, which had been recovering fairly well from the financial crisis, more or less stalled. In 2013, however, growth picked up again — and the British government claimed vindication for its policies. Was this claim justified?