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In page Management:

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At the turn of the twentieth century, the need for skilled and trained managers had become increasingly apparent.[citation needed][1] The demand occurred as personnel departments began to expand rapidly. In 1915, less than one in twenty manufacturing firms had a dedicated personnel department. By 1929 that number had grown to over one-third.[2] Formal management education became standardized at colleges and universities.[3] Colleges and universities capitalized on the needs of corporations by forming business schools and corporate-placement departments.[4] This shift toward formal business education marked the creation of a corporate élite in the US.