A clinic team that is trying to match its capacity (availability of providers) with demand (number of patients requesting appointments on any given day, week, etc.) measures its daily (or weekly) demand and makes predictions about staff levels based on those predictions. Once the staff levels are set, adjustments sometimes need to be made if there are unexpected surges in demand. For example, staff may need to work through lunch or stay later to accommodate an unusual and temporary increase in demand. However, there is no need to change the regular staffing assignments unless there is a clear trend over many days and/or weeks that would indicate an adjustment is needed to meet a demand that has reached a new level (outside of the upper or lower control limits on a control chart).