A popular measure of progress, especially for children, is external assessment of the progress of the pupil by a regular examination. A number of exam boards assess pupils on music theory or practice. These are available for almost every musical instrument. A common method to mark progress is graded examinations for example from grade 1 (beginner) to grade 8 (ready to enter higher study at music school). Some teachers prefer other methods of target-setting for their pupils. The most common is the pupil's concert, which gives experience in playing in public and under a certain degree of pressure, without outright criticism or a more or less arbitrary marking system. Another is the graded system of books followed by teachers of the Suzuki method, in which the completion of each book is celebrated, without a system of marking or ranking of pupils.