labor market is changing in terms of the demand for skills that we have moved very heavily towards intellectual work, new forms of production and also new forms of work organization that require much more skill than they have in the past.” Dr. Levin concluded that for every dollar spent to ensure that students graduate from high school, “there's a return of about six to $7 for society as a whole, just in earnings alone, and that the revenues that are generated are about twice that of the costs.” As to high school dropouts who obtain a General Equivalency Diploma (GED), Dr. Levin testified that “the job prospects and lifetime earnings of the GED certificates is [sic] considerably less than that of the high school graduate. In fact, it is equal or close to that of high school dropouts.” The military, which originated the idea, no longer considers a GED the equivalent of a high school diploma. In addition, the four-year college graduation rate of GED holders is about two percent. 19 Dr. Sobol testified that “preparation for the world of work in this case for sustaining competitive employment has very long been a purpose of the public schools of the United States. * * * [T]he skills that students need in today's world to sustain competitive employment vastly outstrip the level of skill and knowledge that was generally requisite even as short a time as a generation or two ago.” Children in the 21st century “need to understand complex communications technology and be able to use it effectively. They will have to solve problems on the workforce in a changing scene. They will have to apply their knowledge to increasingly new situations. They are unlikely to learn one craft well and practice it for their entire lives but to move about as we see more and more.” Dr. Linda Darling-Hammond, a Professor at Stanford University and Executive Director of the National Commission on Teaching and America's Future, testified that “preparing students for employment has been part of the rationale for public education since the beginning of public education in this country.” She also testified that the findings of abundant research in this area “is that students today need much higher levels of technical skills and knowledge than they did in the past; that that set of skills includes the ability to manage and comprehend complex text and information to manage resources. About 90 percent of the jobs that are in the economy today * * * are jobs that require at least a high school education and a level of technical skill in managing technology, text, and various kinds of content specific competencies that we used to expect of only about 50 percent of the employees in 1950.”