Abstract

AIM To provide a simple method for assessing centile change based on the British 1990 growth reference.

STATISTICAL METHOD The change in SD score over a period of time hasSD 2(1–r) , wherer is the correlation between the first and second SD score. This leads to an SD score for centile change.

DATA Annual height measurements from 2 to 9 years for 318 children from the French longitudinal growth study.

RESULTS The correlations between heights at different ages are higher for shorter measurement intervals and at older ages. The chance of a child’s height centile falling one centile band width is correspondingly smaller for shorter measurement intervals and at older ages. An increase in height measurement error reduces the correlations and dramatically increases the chances of centile crossing.

CONCLUSIONS Quantitative height monitoring based on centile change is provided for whole year periods between 2 and 9 years of age. Effective monitoring requires the measurement error to be as small as possible.