Aggregation, Unit Roots and the Time Series Structure of Manufacturing Real Wages
研究时间加总和截面加总对制造业实际工资数据时间序列特征的影响，发现时间加总效应很大，Altonji和Ashenfelter（1980）以及Nelson和Plosser（1982）的结论可能是加总造成的假象，真实模型更复杂且具有显著周期行为。
The effects of both temporal and cross-sectional aggregation on the estimated time-series characteristics of manufacturing real wage data are examined. The effects, especially of temporal aggregation, are found to be quite large and in accord with statistical theory. The well-known results of J. Altonji and O. Ashenfelter (1980), that real wages are a random walk, and of C. R. Nelson and C. I. Plosser (1982), that real wages are an IMA(1, 1) process, both seem to be entirely artifacts of temporal aggregation, with the true models following processes that are much more complex and that display substantial cyclical behavior. Copyright 1992 by Economics Department of the University of Pennsylvania and the Osaka University Institute of Social and Economic Research Association.