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Testing Fama–French Factors Out of Sample and Choosing Test Portfolios

Article Quant Q&A · Author: Slow Learner

Summary

The discussion asks whether the Fama–French size and value factors remain effective beyond the sample used in their original work. It points to international evidence from Fama and French examining value and momentum across four regions. That study reports regional differences: value premiums generally weakened with firm size outside Japan, momentum appeared broadly outside Japan, and local models described some regional size and value portfolios better than momentum portfolios.

A second cited study reports that the size effect became statistically insignificant after an earlier period and the book-to-market effect after a later one. The answer cautions that significance depends on both the sample period and the portfolios used as test assets. Portfolios sorted on size and book-to-market may remove variation in factor loadings unrelated to those characteristics, reducing the power of the test. It therefore recommends adding portfolios correlated with the proposed factors but not perfectly aligned with those sorts. These are reported findings and methodological arguments, not a single conclusive verdict on whether the factors represent priced risks.

Key ideas

  • Out-of-sample factor performance can vary across regions and sample periods.
  • Reported international evidence finds differences in value and momentum premiums across regions and firm sizes.
  • The apparent significance of size and book-to-market effects depends on the chosen test period and test assets.
  • Portfolios sorted on size and book-to-market may suppress variation in factor exposures unrelated to those traits.
  • Stronger factor tests can include portfolios correlated with the proposed factors but imperfectly correlated with sorting characteristics.

Tags

Full text
# Does Fama French Three Factor Model Work out of Sample (after 1993)?


# Does Fama French Three Factor Model Work out of Sample (after 1993)?












Does anyone know if the Fama-French three factor model has been re-examined empirically after 1993, when the original paper was first published?

I am asking because there seems to be considerable debate about whether the SMB and HML factors represent true risk-factors. It seems to me the best test is to see whether they still work out of sample.

## Answer by vonjd (score 7)

https://quant.stackexchange.com/a/8597

You might want to read this:

Size, Value, and Momentum in International Stock Returns by Fama and French (2011)

> Abstract: In the four regions (North America, Europe, Japan, and Asia Pacific) we examine, there are value premiums in average stock returns that, except for Japan, decrease with size. Except for Japan, there is return momentum everywhere, and spreads in average momentum returns also decrease from smaller to bigger stocks. We test whether empirical asset pricing models capture the value and momentum patterns in international average returns and whether asset pricing seems to be integrated across the four regions. Integrated pricing across regions does not get strong support in our tests. For three regions (North America, Europe, and Japan) local models that use local explanatory returns provide passable descriptions of local average returns for portfolios formed on size and value versus growth. Even local models are less successful in tests on portfolios formed on size and momentum.

## Answer by Mayou (score 4)

https://quant.stackexchange.com/a/8704

In the following paper: "On the Cross-Section of Expected Stock Returns: Fama-French Ten Years Later" (by Chou, Chou, and Wang), the authors found, using the Fama-Mac Beth two-pass regression, that the size effect becomes insignificant during the post-1981 period, and the Book/Market effect becomes insignificant during the post-1990 period.

It is important to note that the statistical significance of the Fama-French factors is not only highly sensitive to the sample period used for testing, but also highly dependent on the test assets used as dependent variables. In both Fama-French papers (1993, 2011), the test assets were double-sorted portfolios formed on size and book/market, and/or size and momentum.

The premise of Fama-French seems reasonable: if there are priced factors that are responsible for the size and value premium, then sorting stocks into portfolios based on their size and book/market ratio are likely to result in diversified portfolios that span the factor space.

The problem is that, by grouping all of the assets with similar size or B/M together, any variation in factor loading that is independent of these two firm-characteristics is largely eliminated.

Therefore, in order to have more powerful tests, the LHS(left-hand side) portfolios should be augmented by portfolios with high correlation to the proposed factors, but with imperfect correlation with size and B/M.

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.