To improve operations, CBP developed a threer-pronged Resource Optimization Strategy. The second prong of the strategy is the Workload Staffing Model, which CBP uses to identify staffing needs for its Office of Field Operations’ CBP Officers at ports of entry. We conducted this audit to determine the reliability of the Workload Staffing Model in establishing the number of CBP Officers needed to fulfill mission requirements. CBP’s Workload Staffing Model includes a sound methodology to determine its staffing needs for CBP Officers and identify staffing shortages. However, the results of the model may not be accurate because CBP cannot ensure that the data entered into the model is reliable. CBP also does not have adequate internal controls over the model. Specifically, CBP’s Office of Field Operations does not (1) catalog, track, and validate all data and systems used in workload calculations; (2) systematically approve changes and additions to the Workload Staffing Model; and (3) have written policies and procedures on developing and using the model. In its December 2013 Strategy and Action Plan (2014 tо 2017), CBP acknowledges concerns about data from other systems used in the Workload Staffing Model.