As Cornish developed the idea of her school, she initially turned to the Montessori-based pedagogical method of Evelyn Fletcher-Copp, but turned at last to the progressive musical pedagogy of Calvin Brainerd Cady, who had worked as musical director with John Dewey as the latter set up his seminal progressive educational project, what is now the University of Chicago Laboratory Schools. Conceived by Cornish as "an elementary school of the arts—all the arts—with music as its major subject," the school initially taught only children, but it soon expanded to functioning also as a normal school (a "teachers' college") under Cady. Within three years it had enrolled over 600 students, expanded the age range of its students to college age, and was the country's largest music school west of Chicago.