Studies have been done to look at the differences in children who have developmental delays versus typical development. Normally when being compared to one another, mental age isn’t taken into consideration. There still may be differences in Developmentally delayed (DD) children vs. Typical development (TD) behavioral, emotional and other mental disorders. When looking compared to MA children there is a bigger difference between normal developmental behaviors overall. DD’s can cause lower MA, so if you compare DD's with TD's it may not be as accurate. When paring up DDs specifically with other children at similar MA it can be more accurate. There are levels of behavioral differences that are considered as normal at certain ages. When we look at DDs and MA kids, we want to see if those with DDs have a larder amount of behavior that isn’t normal for their MA group. Developmental delays tend to contribute to other disorders or difficulties than their TD counterparts.