Depending on the size of the retail store, different job positions may be present. The most common is the sales associate, whose responsibilities include greeting customers, ringing up purchases, and performing basic cleaning duties. Merchandisers or stockers, if the store is large enough, do not spend time at the register, but instead stock merchandise and set shelf displays. Security personnel or asset protection officers patrol the store to curtail shoplifting. Management, meanwhile, oversees the other workers and ensures they are performing their jobs. They also organize and plan shift schedules.