The SOSTAC Planning Model is a planning model that provides a way to plan and manage the tasks in a project. It is used by project managers, planners, and business analysts. SOSTAC Planning Model is an acronym for "Sequence of Operations for Systematic Task Analysis and Cost Estimation." It was first introduced in 1990 by George J. Zsoltan at the University of West Florida. The purpose of this model is to help project managers plan their projects systematically by breaking down the tasks into smaller parts with specific objectives.