The Pea body Picture Vocabulary Test was available in the data set at multiple time points and is a well validated and widely used measure of child
receptive verbal capacity, crucial to understanding an area of cognitive development associated with parenting behavior, and it has been standardized against a national sample of children based on age as a measure of receptive vocabulary.21 The mean PPVT score was 86.4 (SD = 16.4) at age 3 and 93.2 at age 9 (SD = 14.4).