Validation of qualitative methods: Evaluation of repeatability and reproducibility

Applications of statistical methods, such as “Categorical Analysis of Variance” (CATANOVA) and “Ordinal Analysis of Variance” (ORDANOVA), for analysis of test results of qualitative (nominal) and semi-quantitative (ordinal) properties are discussed. These methods can be helpful for validation of test methods - evaluation of repeatability and reproducibility, proficiency testing, development of reference materials with certified qualitative or semi-quantitative properties, evaluation of homogeneity etc., i.e., probably in every field where ANOVA is applied for quantitative properties. The illustrative example is based on a study of freshwater cultured pearls color test results.