Fourth, definitions of maltreatment (a) vary across states and (b) have also been changing over time within states. Variation in definitions across states means that the national estimates we have produced are based not on a single definition of maltreatment, as would be ideal, but on many definitions of maltreatment. Definitional variation over time also means that we are uncertain as to how much of the change in the cumulative risk of confirmed maltreatment is due to actual changes in rates of maltreatment versus changes in definitions of maltreatment. We thus cannot speak with confidence about how the cumulative risk of actual maltreatment has changed over this period.
