About Standard Setting, Cut Score and Statistical Equating
Standard Setting and Cut Score
The passing score for the Art Therapy Credentials Board Examination (ATCB Exam) candidates is determined using the modified Angoff standard-setting method. This approach necessitates that Subject Matter Experts (SMEs) assess each question on the initial test form based on a new content outline to establish the passing score (cut score) for a Minimally Qualified Candidate. In 2025, a new content outline for the ATCB Exam was implemented due to the job task analysis conducted in 2023. In 2025, a standard-setting study was undertaken to establish the cut score for the new exams, coinciding with the introduction of the new content outline.
The passing/cut score obtained through standard-setting on the first test form is applied to other ATCB Exam test forms through statistical equating. Statistical equating adjusts the passing score up or down by accounting for the overall difficulty of each test form. Therefore, statistical equating ensures fairness to all candidates by associating the cut score on a test form with the overall difficulty level of the items on it. With this standard procedure for determining successful candidates on ATCB Exam, the passing scores will vary slightly for each ATCB Exam test form. The cut score for each exam form is unique to that exam. Thus, a candidate’s score on a previous exam does not count toward the cut score on a subsequent exam.
Each version of the ATCB Exam tests the same domains of art therapy practice. However, each exam form contains a different set of test items (questions), meaning that one or more questions on one form may vary in difficulty from the questions appearing on another. The raw score of the ATCB Exam represents the number of correct test questions out of the possible test questions. Even though the examination consists of 175 questions, the score is based on 150 questions. Twenty five questions are “pretest” questions. Pretest questions are included in each examination to obtain statistical information for possible use in future examinations. Pretest questions did not affect exam cut scores.
The ATCB Exam is recruiting Subject Matter Experts to assist with item writing and item review. Learn more on how to become a SME for standard setting.
Statistical Equating
For implementing equating, the Psychometricians use a 25% overlap of items between the base form and the new test form. These common items constitute the equating link between the two forms. Second, they maintain the average difficulty level (p-value) for both forms in close range. The Psychometricians ensure that the new form’s average difficulty is closer to that of the base form. After a sufficient number of candidates attempt the base test form, the Psychometricians use Livingston’s formula for linear equating—Y* = a (X – c) + d—which uses the mean and standard deviation of both base and new forms and the cut score of the base form to reach the cut score of the new form. These measures help the Art Therapy Credentials Board to ensure that the candidates who pass its examination have the knowledge and understanding expected from a board-certified art therapist.