Job Analysis is a process that establishes the skills, knowledge, and experiences that are needed for successful performance in a specific position. It is a best practice in the context of selection assessment - and a critical first step for key hires and/or when large numbers of candidates are expected. 

Competency Modeling takes a broader view and is often is used to define the skill requirements across roles or at organizational levels. A competency model can form the foundation of a "talent pipeline" - a unique framework for integrating talent management and leadership development systems (selection, development, performance management, etc.) across an organization.