The Linkage System is a process that was designed in 1997 to improve academic performance for all students and to enhance work force quality by linking academic content standards to occupational skill standards. The Linkage System is based on research and development conducted by the Vocational-Technical Education Consortium of States (V-TECS). The system's key component is the "Taxonomy of Academic Performance Indicators," which was validated by 18 V-TECS member states through a rigorous review process. The Linkage System includes the following steps: (1) analyze the state-adopted content standards to identify the taxonomy skills that operationally define each mathematics, language arts, and science standard; (2) analyze occupational or vocational-technical program skill standards to identify academic taxonomy skills that are required for competent performance and that are known as related/required academic skills (RAS); (3) crosswalk the occupationally related academic skills to academic content standards; (4) develop instructional/assessment scenarios that include occupational and academic standards; and (5) load the cross-walked materials into the linkage system database (which is under development). The V-TECS system for linking academic content and standards provides rich instructional resources for vocational-technical and academic instructors. Identifying the academic skills required for competent workplace performance provides tools for enhancing the quality of workplace and academic performance. The updated Taxonomy of Academic Performance Indicators that is part of this document contains lists of basic/essential skills in secondary and postsecondary mathematics, language arts, and science, each of which has been assigned a reference code. (Most of the skills added for this edition are in the science domain.) (MN)