Trends, Random Walks and Persistence: An Empirical Study of Disaggregated U.S. Industrial Production
用单位根和方差比检验，分析二战后美国各行业及总体工业生产的趋势特征和持续性，发现不到一半行业产出是随机游走，耐用品行业波动持续性低于非耐用品，总体数据持续性更强。
Unit-root and variance-ratio tests are used to ex- amine the trend properties and degree of persistence of industrial production in U.S. industries and comparable aggregates during the post World War II period. The evidence from unit-root tests suggests that less than one-half of these industries have output which may be characterized as a random walk. The variance-ratio test results generally support this conclusion. Consistent with standard economic theory, fluctuations in durable-goods industries are less persistent than in nondurable goods industries. Finally, tests find relatively greater persistence in the aggregate industrial production data.