Disadvantaged and hard-to-serve adults and youth, including persons with disabilities, have long been primary target populations for education, training, and rehabilitation programs at the federal and state level in the United States. For many years, these programs offered services to these adults and youth through a varied mix of public and private for-profit and non-profit organizations without paying much attention to whether they were achieving the results they were intended to accomplish. Accountability for public funds was generally one of the last policy elements these programs addressed. Since the late 1970s and early 1980s, performance measures and standards, especially outcome-oriented ones, have become increasingly commonplace in these programs.