In previous investigations, we studied the relationships between the profiles of the qualitative responses of in vitro short-term tests (mutation in Salmonella typhimurium, chromosomal aberrations in CHO cells, sister chromatid exchanges in CHO cells, and mutation in mouse lymphoma cells) and common sets of chemicals. In this paper, we address the study of the quantitative responses (potency). We show that two analyses point to similar patterns of relationships: the mutation in mouse lymphoma cells assay is most similar to the CHO sister chromatid exchange assay, and the Salmonella assay is most similar to the CHO chromosomal aberrations assay.