The Quality of Care for Infants and Toddlers (QCIT) observational measure was designed to address the need for a valid and reliable measure of the quality of caregiver-child interactions that could be used in both center-based and family child care (FCC) settings, and with diverse populations. Results from a psychometric field test of 400 classrooms indicated that the QCIT demonstrated strong evidence of reliability and validity. The QCIT was used to capture the quality of caregiver-child interactions for the professional development system We Grow Together. (author abstract)