The Peabody Picture Vocabulary Test - Revised (PPVT - R), administered at the 6.5 - month visit, is a brief vocabulary recognition test, which is strongly correlated with
more comprehensive measures of adult IQ, such as the Wechsler Adult
Intelligence Scale, median r
= 0.72, and is highly stable over a 1 - year period, median r
= 0.72.38 Quality of parenting was evaluated at 12 months on the Home Observation for Measurement of the Environment (HOME), 39 which combines a semi-structured maternal interview with observation of mother - infant interaction.