GH response chart for visualization of Response Scores (RS) on different levels (i.e. growth responses for children with variable individual responsiveness to GH). Left panel: The RS chart is given with 'isolines' ('channels') for RS = 1, 2, 3 and 4 which is indicated in the figure. For the individual child at treatment time 1 year (x-axis), the observed growth response (Δheight SDS) is found on the y-axis to the left and following the corresponding curve the individual RS can be found to the right. Middle panel: Observed first-year Δheight SDS on treatment for three prepubertal children from the validation group (filled circles). The individual calculated Response Score (dotted line) is found on the right axis. The function for the Response score is: RS(t) = (Δheight SDSobs - FBG(t))/FCU(t), where FBG(t) = elog (1 + t*(0.205 - 1/(1 + 2.1*t))) and FCU(t) = t/(t + 0.894); t = GH treatment time in years. Right panel: Individual Response Scores from the same three children, based on observed Δheight SDS on treatment at different time points (filled circles at treatment time 2, 3, 4, 5 and 6 years) in comparison with the predicted (dotted line). Response Score was consistent over time within an individual child, and the inclusion in the model of measurements made later than 1 year after the start of GH treatment are acceptable.