6.1 Item selection
The items available to measure early child development orignate from many different instruments. Each original instrument was aimed at measuring the same construct, so inevitably, many items do overlap between instrument. These overlapping items are useful to align the different instrument (see booklet II for all steps involved), but for creating an instrument, many items that ask about exactly the same milestone is superfluous. So within groups of items that asks bout the same milestone, one item can be selected to represent the milestone in the instrument. In the dinstrument application, this pre-selection can be made previous to the actual item selection. It is also an option to skip this step and do this at the same time of the item selection.