The Infant/Toddler Environment Rating Scale®, Revised (ITERS-R) is a thorough revision of the original Infant/Toddler Environment Rating Scale (ITERS, 1990). It is one of a series of four scales that share the same format and scoring system but vary considerably in requirements, because each scale assesses a different age group and/or type of child development setting. The ITERS-R retains the original broad definition of environment including organization of space, interaction, activities, schedule, and provisions for parents and staff. The 39 items are organized into seven subscales: Space and Furnishings, Personal Care Routines, Listening and Talking, Activities, Interaction, Program Structure, and Parents and Staff. This scale is designed to assess programs for children from birth to 30 months of age, the age group that is most vulnerable physically, mentally, and emotionally. Therefore, the ITERS-R contains items to assess provision in the environment for the protection of children's health and safety, appropriate stimulation through language and activities, and warm, supportive interaction.

Admittedly, it is very challenging to meet the needs of infants and toddlers in a group care setting because each of these very young children requires a great deal of personal attention in order to thrive. The economic pressure of raising a family continues to make the use of out-of-home group care for infants and toddlers the norm rather than the exception. Therefore, as a society, we are increasingly aware that we must face the challenge of providing child care settings for very young children that promote optimal development. It has long been the personal challenge of professional early childhood educators to provide the nurturance and stimulation that very young children need on a daily basis. A comprehensive, reliable, and valid instrument that assesses process quality and quantifies what is observed to be happening in a classroom, can play an important role in improving the quality of infant/toddler care.

In order to define and measure quality, the ITERS-R draws from three main sources: research evidence from a number of relevant fields (health, development, and education), professional views of best practice, and the practical constraints of real life in a child care setting. The requirements of the ITERS-R are based on what these sources judge to be important conditions for positive outcomes in children both while they are in the program and long afterward. The guiding principle here, as in all of our environment rating scales, has been to focus on what we know to be good for children.