A comparative study of the fit of four different functions to longitudinal data of growth in height of Belgian girls.

We have fitted Preece-Baines model 1, double logistic, logistic and Gompertz functions to longitudinal data on the growth in height of 35 Belgian girls, followed from birth to 18.0 years. The Preece-Baines model 1 showed significantly lower residual mean squares than the double logistic function, when fitted to data beyond the age of 1.0 year. The former model was also most robust towards variations in the lower age bound by the subject's data series and always described the adolescent spurt better than the latter. Both models fitted the data badly when measurements before the age of 1.0 year were included, and they usually estimated the point at take-off too early. Over the adolescent cycle, only, the logistic function fitted our data slightly better than the Gompertz function, with significantly lower pooled residual mean squares, though a slightly worse performance in the runs-test.