TY  - JOUR
AU  - Long,J. Bradford De
AU  - Shleifer,Andrei
AU  - Summers,Lawrence H.
AU  - Waldmann,Robert J.
TI  - The Survival of Noise Traders in Financial Markets
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 2715
PY  - 1988
Y2  - September 1988
UR  - http://www.nber.org/papers/w2715
L1  - http://www.nber.org/papers/w2715.pdf
N1  - Author contact info:
J. Bradford DeLong
Department of Economics
601 Evans Hall
University of California, Berkeley
Berkeley, CA 94720-3880
Tel: 510/643-4027
Fax: 510/642-6615
E-Mail: delong@econ.berkeley.edu

Andrei Shleifer
Department of Economics
Harvard University
Littauer Center M-9
Cambridge, MA 02138
Tel: 617/495-5046
Fax: 617/496-1708
E-Mail: ashleifer@harvard.edu

Lawrence H. Summers
Harvard Kennedy School of Government
79 JFK Street
Cambridge, MA 02138
Tel: 617/495-9322
Fax: 617/495-0436
E-Mail: lhs@harvard.edu
AB  - We use the revised estimates of U.S. GNP constructed by Christina Romer (1989) to assess the time-series properties of U.S. output per capita over the past century. We reject at conventional significance levels the null that output is a random walk in favor of the alternative that output is a stationary autoregressive process about a linear deterministic trend. The difference between the lack of persistence of output shocks either before WWII or over the entire century, on the one hand, and the strong signs of persistence of output shocks found by Campbell and Mankiw (1987) and by Nelson and Plosser (1982) for more recent periods is striking. It suggests to us a Keynesian interpretation of the large unit root in post-WWII U.S. output: perhaps post-WWII output shocks appear persistent because automatic stabilizers and other demand-management policies have substantially damped the transitory fluctuations that made up the pre-WWH Bums-Mitchell business cycle.
ER  -