This research synthesis reviews how employers, educators, and professional and labor organizations have adapted general work readiness, industry core, occupational cluster, and specific occupational skills to design and implement a skill standard system. Its primary goal is to describe and analyze a continuum of alternatives for conceptualizing skill standards. Following an introduction, section 2 reviews private- and public-sector efforts to identify and draft academic and employability skill standards. It considers the relationship between industry and academic skill standards and the requirements of high performance work organizations on skill standard development and implementation. Section 3 reviews proposals for developing an industry-based skill standard system for education and describes some approaches that educators are presently using to implement comprehensive skill standard systems. Section 4 characterizes different frameworks that standard developers use to formulate and organize occupational cluster standards for education. It uses clusters from selected educational programs and national, state, and industry standards projects to illustrate issues related to standard development and implementation. Section 5 examines how developers define and implement occupationally specific standards in practice and addresses the relationship between education and industry-defined skill standards. Contains 130 references. (YLB)