Probability estimation of final height

13,707 longitudinal records of individuals (6,749 boys and 6,958 girls) from 6 years to 17 years were fitted by means of a smoothing cubic spline function and the factors influencing the change in height SDS during puberty were analysed. Children are divided into subgroups with 0.2 SD intervals according to height SDS at 6 years. Shorter children in subgroups at 6 years tend to increase their final height SDS by entering puberty later and making their height at onset of pubertal growth spurt (PGS) relatively taller. On the other hand taller children in subgroups at 6 years tend to decrease their final height SDS by entering puberty early and make height at PGS relatively shorter. The percentage distribution of a final height SDS against subgroups at 6 years also shows this tendency. This figure is useful in predicting the probability of final height SDS in the clinical field of growth disorders.