In this paper, detailed comparisons are given between those estimators that can be derived from the principal component two-parameter estimator such as the ordinary least squares estimator, the principal components regression estimator, the ridge regression estimator, the Liu estimator, the r − k estimator, and the r − d estimator by the prediction mean square error criterion. In addition, conditions for the superiority of the principal component two-parameter estimator over the others are obtained. Furthermore, a numerical example study is conducted to compare these estimators under the prediction mean squared error criterion.
KEYWORDSLiu estimator, prediction mean squared error, ridge regression estimator, r − d estimator, r − k estimator, two-parameter estimator 1 Concurrency Computat Pract Exper. 2019;31:e4710.wileyonlinelibrary.com/journal/cpe( 1 +1) 2 ( 1 +k) 2 is always true, so, for any values of z 2 01 , z 2 02 , 2 2 , k, and d, we have J PCTP < J r − k .Theorem 6. For any value of z 2 01 , z 2 02 , 2 2 , k, d, and 1 , we have J PCTP < J r − d .