NPR: The government’s “cash for clunkers” program boosted auto sales by 360,000 during the two months it was in place, according to a new study. But in the seven months that followed, sales were down by 360,000 compared with what they would have been without the program, the study found. The implication: The program didn’t bring new buyers into the market. But it encouraged people who would have bought a car anyway to make their purchase a few months sooner. Under the …