In 1880, American high schools were preparatory academies for colleges, but by 1910 they had been transformed into core elements of the common school system. The explosive growth brought the number of students from 200,000 in 1890 to 1,000,000 in 1910, to almost 2,000,000 by 1920; 7% of youths aged 14 to 17 were enrolled in 1890, rising to 32% in 1920. The graduates found jobs especially in the rapidly growing white-collar sector. Cities large and small across the country raced to build new schools. Few were built in rural areas, so ambitious parents moved close to town to enable their teenagers to attend. After 1910, vocational education was added, as a mechanism to train the technicians and skilled workers needed by the expanding industrial sector.
College preparation
In the 1865-1914 era, the number and character of schools changed to meet the demands of new and larger cities and of new immigrants strange to American ways, and to adjust to the new spirit of reform permeating the country. High schools increased in number, adjusted their curriculum to prepare students for the growing state and private universities; education at all levels began to offer more utilitarian studies in place of an emphasis on the classics. John Dewey and other Progressives advocated changes from their base in teachers' colleges.
Before 1920 most secondary education, whether private or public, emphasized college entry for a select few headed for college. Proficiency in Greek and Latin was emphasized. Abraham Flexner, under commission from the philanthropic General Education Board (GEB) wrote A Modern School (1916) calling for a deemphasis on the classics. The classics teachers fought back in a losing effort.
German was preferred as a second, spoken language prior to World War I. An anti-German attitude that resulted from the war, promoted French as a second language instead. French survived as the second language of choice until the 1960s, when Spanish became popular.
The growth of human capital
By 1900 educators argued that the post-literacy schooling of the masses at the secondary and higher levels, would improve citizenship, develop higher-order traits, and produce the managerial and professional leadership needed for rapid economic modernization. The commitment to expanded education past age 14 set the U.S. apart from Europe for much of the 20th century.
From 1910 to 1940, high schools grew rapidly in number and size, reaching out to a broader clientele. In 1910, for example, only 9% percent of Americans had a high school diploma; in 1935, the rate was 40%. This phenomenon was uniquely American; no other nation attempted such widespread coverage. The fastest growth came in states with greater wealth, more homogeneity of wealth, and less manufacturing activity than others. The high schools provided necessary skill sets for youth planning to teach school, and essential skills for those planning careers in white collar work and some high-paying blue collar jobs. Economist Claudia Goldin argues this rapid growth was facilitated by public funding, openness, gender neutrality, local (and also state) control, separation of church and state, and an academic curriculum. The wealthiest European nations such as Germany and Britain had far more exclusivity to their education system and few youth attended past age 14. Apart from technical training schools, European secondary schooling was dominated by children of the wealthy and the social elites.
The United States chose a type of post-elementary schooling consistent with its particular features — stressing flexible, general and widely applicable skills that were not tied to particular occupations and geographic places had great value in giving students options in their lives. Skills had to survive transport across firms, industries, occupations, and geography in the dynamic American economy.
Public schools were funded and supervised by independent districts that depended on taxpayer support. In dramatic contrast to the centralized systems in Europe, where national agencies made the major decisions, the American districts designed their own rules and curricula.
Teachers
Support for the high school movement occurred at the grass-roots level of local cities and school systems. The federal government involvement included vocational education funding after 1916. States and religious bodies funded teacher training colleges, often called "normal schools". They morphed into state colleges with a broad curriculum after 1945.
Teachers organized themselves during the 1920s and 1930s. In 1917, the National Education Association (NEA) was reorganized to better mobilize and represent teachers and educational staff. The rate of increase in membership was constant under the chairmanship of James Crabtree—from 8,466 members in 1917 to 220,149 in 1931. the rival American Federation of Teachers (AFT), was based in large cities and formed alliances with the labor unions there. The NEA saw itself as an upper-middle-class professional organization, while the AFT identified with the working class and the union movement.