Using the LMS method to measure skewness in the NCHS and Dutch National height standards.

The American National Center for Health Statistics (NCHS) and Dutch national height growth standards, unlike previous standards, allowed for skewness when fitting the centile curves. The LMS method (Cole 1988) is a way of summarizing growth standards which monitors the changing skewness of the distribution during childhood. It does so by calculating the Box-Cox power needed to transform the data to normality at each age, and displaying the results as a smooth curve of power plotted against age. Applying the LMS method to the NCHS and Dutch standards highlights the nature of the changing skewness of height during childhood, and particularly during puberty. Taken in conjunction with curves for the mean and coefficient of variation of height plotted against age, the power curve allows the original centiles to be reconstructed to high accuracy. This provides further evidence that the LMS method is a powerful and compact technique for deriving and presenting growth standards.