“…(i) It protects against overshrinking by smoothly weighting â(k) and â according to the F-statistic we would use for making a preliminary test of model (1) vs model (2) (Sclove et al, 1972;Bock et al, 1973;Yancey & Judge, 1976). (ii) It is an empirical Bayes estimator which incorporates prior beliefs both in (2) and that the explanatory variables are intrinsically correlated as in the observed X (Raiffa & Schlaiffer, 1961;Tiao & Zellner, 1964;Efron & Morris, 1973;Zellner, 1983;Oman, 1984Oman, , 1985. (iii) Because â Ã (k) is a Stein estimator, PMSE( â Ã (k), â) , PMSE( â, â) for all â, where for an estimator â Ã , PMSE( â Ã , â) Ei X â Ã À X âi 2 .…”