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Sample‐Dependent Results Using Accounting and Market Data: Some Evidence
Author(s) -
BANZ ROLF W.,
BREEN WILLIAM J.
Publication year - 1986
Publication title -
the journal of finance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 18.151
H-Index - 299
eISSN - 1540-6261
pISSN - 0022-1082
DOI - 10.1111/j.1540-6261.1986.tb04548.x
Subject(s) - base (topology) , accounting , econometrics , selection bias , sample (material) , selection (genetic algorithm) , computer science , economics , statistics , mathematics , mathematical analysis , chemistry , chromatography , artificial intelligence
Studies relating accounting and price data often use the COMPUSTAT or related PDE data base as the source for the accounting data. This practice may introduce a look‐ahead bias and an ex‐post‐selection bias into the study. We examine this problem by comparing results from the standard COMPUSTAT data base with those from a data base which suffers from neither bias. We find that rates of return from portfolios chosen on the basis of accounting data from the two data bases differ significantly. Further, we find that these differences imply different conclusions when we test a specific hypothesis relating accounting and price data. Finally, we propose a number of remedies which may reduce the bias when the standard COMPUSTAT data base is used.