BASE is carried out on a one-to-one basis with a teacher, teaching assistant or an appropriate adult. Ideally, it should be done in a quiet corner. The assessment is presented by a character, “Milly the Bug”, who asks the child questions. However, the adult is in control of the computer at all times and uses the mouse and the on-screen buttons to mark the answers the child gives as right or wrong.
The assessment is adaptive to each child so as it progresses, the questions gradually get more difficult. When the child starts getting them wrong, it will stop asking harder questions in that section, move onto the next section, and start again with easier questions.