E for Effort (1940)

[Grant Barrett]

  I feel compelled to respond that my entire elementary, middle and high
school school experience included the E, S, M, I, F scale, in which E
was the best grade, not the A, B, C, D, F scale.

E in our schools may have originally stood for Excellent (not Effort),
but the letters, especially the M, were somewhat divorced from their
origins. The M's problem: Mediocre? Medium? Middling? Median? Maybe
you'll go to college, Maybe you won't?

Grant