THE recent global crisis—the deepest and most widespread since the 1930s by any measure—has refocused attention on spillovers across countries. Did the size and nature of financial problems lead to a synchronized global downturn? Put another way, if we had anticipated the large U.S. (and U.K.) financial meltdown before the crisis, would we have predicted a synchronized global slowdown? There are good reasons to answer this question with a firm “yes.”