An intervention group participated in the Number in Nappiesprogramme and their performance on the composite scales ofthe Bayley Scales of Infant and Toddler Development – ThirdEdition (BSID – III) was compared before and after theintervention. The performance of the intervention group wasalso compared to that of a control group before the intervention(to ensure that the groups were matched in terms of ability)and after the intervention (to determine the impact of theprogramme).