This report contains reliability and validity evidence for the North Carolina Kindergarten Entry Assessment system (KEA) using a statewide sample of kindergarten children. The KEA was designed as a formative, developmental, authentic, and criterion referenced classroom resource for teachers. As a formative assessment, the KEA focuses on the learning process and is used to support learning while learning is taking place. It is a tool to support teachers and students, and helps provides valuable feedback to inform and adjust both teaching and learning. This study focused on the following research questions in an effort to begin to understand the rating scale category effectiveness of the KEA progressions as used by North Carolina kindergarten teachers: (1) What are the characteristics of the distributions of placements on each of the progressions? (2) Do the mean total scores of the children placed in each category increase monotonically along the rating scale for each of the progressions? (3) Do the thresholds between rating scale categories increase monotonically along the rating scale for each of the progressions? and (4) Do the category probability plots indicate distinct probability distributions for each rating scale point for each of the progressions? The results of the analyses related to dimensionality and reliability are all very strong and reflect very positively on the use of a total score for psychometric research purposes such as those outlined in this report. The results related to item or progression difficulty estimates were generally positive, though they suggest a need for a greater range of progression difficulties. The results of the examination of rating scale category effectiveness were mixed.