An employment-immigration concept defining eligibility requirements for work-based immigration benefits. It governs labor market testing, wage standards, job requirements, and petition adjudication criteria for qualifying categories. It does not authorize work or status absent required approvals and the necessary subsequent issuance or adjustment steps. It determines access to work-based visas or permanent residence and affects compliance obligations for employers and applicants. The concept is generally stable, though category criteria and evidentiary expectations may evolve over time.