What evidence supports the claim that the Soviet Union made great educational progress?

Education in the Soviet Union was guaranteed as a constitutional right to all people provided through state schools and universities. The education system which emerged after the establishment of the Soviet Union in 1922 became internationally renowned for its successes in eradicating illiteracy and cultivating a highly educated population. Its advantages were total access for all citizens and post-education employment. The Soviet Union recognized that the foundation of their system depended upon an educated population and development in the broad fields of engineering, the natural sciences, the life sciences and social sciences, along with basic education.