In the article, “The Why and How of Z Scores,” by Colan, J Am Soc Echocardiogr 2013;26:38-40, the second sentence in the first paragraph on page 40 contains an error. The correct sentence should be “We undertook a comprehensive exploration of this issue ⁵ and found that both theoretical considerations and empirical observations indicated that BSA is superior to height or weight alone as an allometric variable in normal subjects, that the Haycock formula ⁷ for BSA was superior to the other published formulas, and that exponential equations of the form Y = α x BMI ^b + c provided the best descriptor for all anatomic cardiac measurements.