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Journal of Financial Economics Vol. 19 No. 2 1987

Subperiod aggregation and the power of multivariate tests of portfolio efficiency

Michael R. Gibbons1; Jay Shanken2

1 Stanford University · 2 University of Rochester

Abstract

When testing portfolio efficiency, empiricists usually perform tests using subperiods and aggregate the results in some manner. Although the power of individual subperiod tests has been studied previously, little is known about the power of the aggregate test. Power is evaluated here through simulations using two different aggregation techniques. Aggregate power is substantially higher than that for a single subperiod. For example, in one scenario the aggregate power is 0.77 over a sixty-year period, but only 0.17 for each five-year subperiod. In addition, the level of power depends on the method of aggregation.

DOI
10.1016/0304-405x(87)90011-0
Volume
19
Issue
2
Pages
389-394
Language
en
Sources
bibtex:phds-export.bib openalex crossref

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