The Job Zone classification provides O*NET users a guide to the vocational preparation levels (e.g., education, training, and work experience) of O*NET-SOC occupations. With each new O*NET database update, approximately 100 occupations are classified or re-classified within the vocational preparation five-level Job Zone system. This document provides a detailed description of the procedure by which incoming O*NET data and other information contribute to the assignment of occupations to Job Zones.