This research study was conducted to provide information on school readiness. While there is no national definition for school readiness, states and organizations have developed various definitions to highlight readiness skills that have been deemed important for kindergarteners. The early childhood developmental domains that are often cited in these individual definitions are physical (fine/gross motor), social-emotional, cognition (academics), and communication skills. By considering a holistic approach of school readiness, a child’s development is not isolated to mastering one domain to be “ready” for school. While most states do not have a statutory school readiness definition, many have been measuring school readiness skills for several years. In the 1980’s, a number of states screened or tested children’s readiness skills using standardized assessments before kindergarten entry. In the 1990’s, the attention moved from using a child’s score to determine their placement to assessing a child’s strengths and weaknesses in various skill areas that were associated with identified school readiness criteria. Over the last few years, the focus has continued to shift to include monitoring state-wide school readiness levels and guiding planning and instruction. With no universal definition of school readiness, no universal school readiness measurement instrument exists. However, there are school readiness instruments currently being developed to address the needs of states and school districts. The need for reliable and valid instruments to focus on the various developmental skill levels of young children across domains is apparent. The school readiness instrument, the AEPS (Assessment Evaluation Programming System)-3 Ready, Set 4.0, is being developed to do just that, providing a holistic approach to measuring school readiness. Skills in the following areas are to be assessed on the AEPS-3 Ready, Set 4.0: gross motor, fine motor, adaptive, cognitive, social-communication, social-emotional, literacy, and math. The instrument is to be used by kindergarten teachers to access students in the categories listed above once the school year starts. The information gathered from the AEPS-3 Ready, Set 4.0 would provide teachers with authentic, holistic data on the school readiness skills of children in their class. Through teacher surveys, this school readiness study aimed to answer if field users agreed on the content of the AEPS Ready, Set 4.0 in terms of sequence, breadth, clarity, relevance, and functionality and if field users agreed on the scoring, item and criteria, and usefulness of the AEPS Ready, Set 4.0 for its intended purposes.