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TESTS FOR ROBUST VERSUS LEAST SQUARES FACTOR MODEL FITS. R . Douglas Martin* Computational Finance Program Director Departments of Applied Mathematics and Statistics University of Washington doug@stat.washington.edu R-Finance 2014 May 16, 2014, Chicago
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TESTS FOR ROBUST VERSUS LEAST SQUARES FACTOR MODEL FITS R. Douglas Martin* Computational Finance Program Director Departments of Applied Mathematics and Statistics University of Washington doug@stat.washington.edu R-Finance 2014 May 16, 2014, Chicago * Joint work with Tatiana Maravina (PhD, Boeing Company) and Kjell Konis, Department of Applied Mathematics University of Washington.
Time Series Factor Models Robust M-Estimates UselmRobin package robust
Favorite Rho and Psi Functions Optimal bias robust: Svarc, M., Yohai, V. J., & Zamar, R. H. (2002).
Test Statistic T1 (Hausman-type) H1: Errors have a normal distribution K1: Errors have a symmetric or skewed non-normal distribution K2: Joint distribution of asset and factor returns is bias producing Efficient under H1 (see Hausman, 1978) Test Statistic T2 (Wald-type) H2: Errors have a normal distribution or a non-normal distribution K2: Joint distribution of asset and factor returns is bias producing
R-Implementation New functions in package robust (Kjell Konis), to be submitted to CRAN by Sunday 5/18: lsRobTest > args(lsRobTest) function (object, test = c("T2", "T1"), ...) Object = an lmRob fitted model object
> lsRobTest(fit.mm, test="T1") Test for least squares bias H0: normal regression error distribution Individual coefficient tests: LS Robust Delta Std. Error Stat p-value x 1.497 1.798 -0.3009 0.009612 -31.31 3.889e-215 > lsRobTest(fit.mm, test="T2") Test for least squares bias H0: composite normal/non-normal regression error distribution Individual coefficient tests: LS Robust Delta Std. Error Stat p-value x 1.497 1.798 -0.3009 0.08383 -3.589 0.0003315
References Bailer, Maravina and Martin (2011). “Robust betas in asset management”, Handbook of Quantitative Asset Management, Oxford University Press. Maravina and Martin (2014). “A Hausmantype test of robust versus least-squares regression fits”, submitted to SSRN on 5/18/2014. Maravina and Martin (2014). “A Wald type test of robust versus least-squares regression fits”, in preparation.