Before revision:  We give conditions under which such estimators are consistent, and describe their asymptotic mean squared error properties . Analytic examples illustrate the situations where re-weighting provides a reduction in variance , and a simulation study is conducted to evaluate small sample performance of the proposed estimators .
After revision:  We give conditions under which such estimators are consistent, and describe their asymptotic mean squared error properties . Analytic examples illustrate the situations where re-weighting provides a reduction in variance together with proofs of the results in the paper .