The routine is marked out of 10 by five judges with deductions for incomplete moves or poor form. Usually the highest and lowest scores are discarded. Additional points can be added depending on the difficulty of the skills being performed. The degree of difficulty (DD or tariff) is calculated by adding a factor for each half turn (or twist) or quarter somersault. Difficulty is important in a routine, however, there are differences in opinion between various coaches whether it is better to focus on increasing the difficulty of routines given that this usually results in a reduced form score or to focus on improving execution scores by displaying better form in an easier routine.