Skupski DW, et al. – Analysts compare the precision of a new formula with one developed in 1984 (and still in common use) and aim to develop and compare racial and ethnic–specific and racial and ethnic–neutral formulas. The National Institute of Child Health and Human Development (NICHD) gestational age estimation formula is related to smaller errors than a well–established historical formula. Racial and ethnic–specific formulas are not superior to a racial–ethnic–neutral one.