Estimate activity resource focuses exclusively upon the identification of the number of human resources required to perform each scheduled activity

"Estimating effort, time and resources needed (and available) for scheduled activities. After Define Activities, before Develop Schedule Inputs: Activity List, Activity Attributes, Resource Calendars, Enterprise Environmental Factors Tools: Expertise, Alternatives Analysis, Published Estimating Data, Bottom-Up Estimating, Project Management Software Outputs: Activity Resource Requirements, Resource Breakdown Structure, Project Documet Updates"