7 The relative importance of permanent (trend) versus cyclical shocks 8 to GDP has been a central issue in macroeconomics since the work 9 of Nelson and Plosser (1982). Morley et al. (2003) find large trend 10 shocks. In contrast, Perron and Wada (2009) argue that allowing for 11 a onetime change in the mean growth rate at 1973:1 nearly eliminates 12 evidence for any trend variance. We re-estim...
