Teachers have it made. They get to send students to detention, assign homework and give tests. They can issue commands like "compare and contrast" and watch their charges squirm. There is but one drawback to wielding such power: the daunting task of grading essays. For every student who pulls an all-nighter wading through Great Expectations, there is a teacher who has to slog through dozens of tortured expositions on the symbolism of Miss Havisham's aborted wedding feast.
That may soon change. America's most relentless examiner, the Educational Testing Service, has developed computer software, known as E-Rater, to evaluate essays on the...