CONSISTENCY IN STATISTICAL ANALYSIS OF STANDARDIZED TOXICITY STUDIES

Abstract

Two statistical methods are described and discussed for preparing data from continuous toxicity studies with standard experimental design to be analyzed statistically by parametric methods. Both methods are intended to bring consistency to thepreclinical area of drug development by standardizing thestatistical methods used to assess the results. The first method is a Box-Cox transformation method in which responses are transformed to achieve homoscedasticity; the second method is a power-of-the-mean modeling of the variance. The two methods are comparable regarding homoscedasticity and homogeneity across studies. However, they have different advantages and drawbacks. The most important advantage of the power-of-the-mean model compared with the Box-Cox transformation is that results from theanalyses areon thesamescaleas theoriginal measurements. Hence, the comparability of results from different studies is facilitated. Empirical analyses have been performed for different studies and responses to compare and assess the two methods.

Keywords: :

• Toxicity Studies;Transformation;Consistency Standardization;Variance Stabilization