ABSTRACT
In practice, one may be able to make a choice between bp and bw by comparing bp and bw and performing a Hausman-type specification test. This amounts to doing an artificial regression of the type
y = X/3 + WXy + u (89)
and testing for y = 0 by the standard F -test. Alternatively, one can combine the two by using Stein-type shrinkage estimators as
( c) c bs = 1 - F bp + Fbw (90) The properties of bs are not known, but they can be developed by following Judge and Bock (1978) or Vinod and Ullah (1981).
