Construction of LMS parameters for the Centers for Disease Control and Prevention 2000 growth charts.

OBJECTIVES

In 2000, the Centers for Disease Control and Prevention (CDC) released a new set of childhood growth charts for the United States. These charts included a set of smoothed percentiles along with LMS (lambda-mu-sigma) parameters to allow the calculation of other percentiles or standard deviation scores. These parameters resemble the LMS parameters derived using Cole's LMS method. Similarities in the terminology mask differences in the methods used. This brief commentary is intended to clarify these differences.

DISCUSSION

The background for the creation of standard deviation scores (z scores) for growth charts is discussed, and the method used to create the CDC LMS parameters is compared with Cole's LMS method.

CONCLUSION

Using an approach similar to that used by CDC, LMS parameters could be calculated for any set of fitted percentile curves, regardless of the smoothing methods employed to create the curves. However, this is not equivalent to using the LMS method.