5.5 Age band

Informative items to measure early child development vary a lot by age. Asking a 3 month old if he or she can walk stairs is not very informative, neither is asking a 3 year old if he can roll from back to stomach. As discussed in the previous paragraph, it is therefore important to select items all over the D-score range. That way, easier items such as “can roll from back to stomach” can be asked to younger children, and more difficult items, such as “can walk stairs” can be asked to older children. Early child development increases by age, however this increase by age is not linear. Development increases very fast in the first year, but in the following years, the growth in development slows down. This relation between age and development is very important to consider in the selection of items and creating an instrument.