Many experimental programs aim to accelerate the growth of individuals on some dimension of interest. Random assignment of subjects to the program and control group assures an unbiased comparison between treatments. Without randomization there may be ...
Many experimental programs aim to accelerate the growth of individuals on some dimension of interest. Random assignment of subjects to the program and control group assures an unbiased comparison between treatments. Without randomization there may be important differences between groups in terms of pretreatment or selection characteristics and growth potential. In the non-test comparison based mainly on pretest measures. It is the purpose of this paper to consider the adequacy of various statistical techniques proposed, from the alternative assumptions about the nature of growth, so the performance of various commonly used methods is examined. It is concluded that statistical adjustments are generally inadequate in non-equivalent growth systems across treatment groups.