The Workload Indicators of Staffing Needs (WISN) process and methodology were developed over 15 years ago by the World Health Organization as a human resources management and planning tool. Traditional methods of determining staffing needs include calculating population-to-staff ratio and standards based on the type of health facility. WISN estimates staffing requirements by cadre in a health facility based on the actual workload for that facility and locally defined activity (time) standards.