Resumen
Zhou and Qin [2004. New intervals for the difference between two independent binomial proportions. J. Statist. Plann. Inference 123, 97-115; 2005. A new confidence interval for the difference between two binomial proportions of paired data. J. Statist. Plann. Inference 128, 527-542] ''new confidence intervals'' for the difference between two treatment proportions exhibit a severe lack of invariance property that is a compelling reason not to use them.