Chapter 10 Robust Regression 503 10.12 A Criticism of Methods with a High Breakdown Point It seems that no single method is free from criticism, and regression methods that have a high breakdown point are no exception. A potential problem with these methods is that standard diagnostic tools for detecting curvature, by examining the residuals, might fail (Cook, Hawkins, & Weisberg, 1992; McKean et al., 1993). Thus, it is recommended that if a regression method with a high breakdown point is used, possible problems with curvature be examined using some alternative technique. Some possible ways of checking for curvature, beyond the standard methods covered in an introductory regression course, are described in Chapter 11. 10.13 Some Additional Estimators Some additional regression estimators should be outlined. Although some of these estimators have theoretical properties that do not compete well with some of the estimators already described, they might have practical value. For instance, some of the estimators listed here have been suggested as an initial estimate that is refined in some manner or is used as a preliminary screening device for detecting regression outliers. Graphical checks suggest that