TreeTest™ is an external assessment for measuring achievement and growth in K–12 Mathematics, English Language, and science. At any time of the academic year, students will participate in three test sessions to assess Mathematics, English Language, and science. When taking the TreeTest™, the difficulty of each question is based on how well a student answers all the previous questions. As the student answers correctly, questions become more challenging. If the student answers incorrectly, the questions become easier. Although the tests are timed, it takes students one hour to complete each of the three tests (20 minutes for each session).