APA Dictionary of Psychology

see Bayley Scales of Infant and Toddler Development.

a standardized assessment instrument in which an observer (e.g., parent, teacher, clinician, or the individual) rates the frequency, intensity, or severity of specific behaviors using predefined response options, typically on a numerical or Likert-type scale. Behavior rating scales are used to quantify observable behaviors, support diagnosis, monitor change over time, and inform clinical or educational decision-making. Behavior rating scales are a type of behavioral assessment tool used to quantify one or more observable behaviors in a given situation or at a given time, to support diagnosis, monitor change over time, and inform clinical or educational decision-making.