The use of the NCHS standard to assess weight-for-height in children is equivalent to expressing the child’s weight and height, in the ratio W/Hp, as a fraction of the NCHS median W/Hp for age, where the power p of height changes with age. It falls from a value of 3 at birth to 1.5 at 18 months, and then rises to 3 again by 11 years. Its discontinuous pattern of change in the second six months of life leads to potentially misleading assessments of weight-for-height in very tall or very short children. Weight for height standards in general, and the NCHS standard in particular, should not be used to assess weight-for-height in young children. The index W/H2, expressed as a fraction of the NCHS median W/H2 for age, should be used instead.
Cole, T J.
"A Critique of the NCHS Weight for Height Standard,"
2, Article 6.
Available at: https://digitalcommons.wayne.edu/humbiol/vol57/iss2/6