The National Center for Education Statistics defines correspondence as "a method of instruction with students receiving structured units of information and accompanying material completely through the mail." A correspondence course is the completion of a study plan, including completing credit courses towards a degree or certificate, via this method. Correspondence courses can also be referred to distance education. Distance learners often have physical or electronic access to college or university resources, including libraries.
Distance education in the United States can be traced to correspondence and individual study in the 1700s. Initially, it involved non-credit instruction for adult learners in specific areas, such as mining, agriculture, other technical subjects. Students and instructors communicated by mail, and it was the student's responsibility to prepare assignments or tests. The first formal correspondence courses were likely linked to the Chautauqua Literary and Scientific Circle, which was established in 1878.
As technology evolved, correspondence courses adopted the use of audiovisual technology. For example, by the 1980s and 1990s, distance education courses often involved some degree of teleconferencing and videoconferencing. The use of video and audio aides also began to be used in the early half of the 20th Century. With the proliferation of Internet use, colleges and universities now generally offer correspondence-type courses through online courses and instruction.
Correspondence schools are organizations that provide correspondence courses. They are often private, for-profit proprietary schools. Some public institutions also provided correspondence courses and even full programs by mail, including the University of California and the University of Oklahoma. At their peak, correspondence schools in the United States number more than 1,000 and served approximately five million students. Today, most correspondence schools are Internet-based distance education or learning schools. The eighth annual Sloan Survey of Online Learning showed that approximately 5.6 million students in the U.S. were enrolled in at least one online course in fall 2009.