The education ministry of Hesse publishes a Fehlerindex, an error index, for judging the correctness of language in written work für alle Unterrichtsfächer, for all school subjects, in grades 9 and 10. It applies to written work of at least 100 words. The teacher counts the errors, multiplies the number by 100 and divides it by the number of words.
Above a set index, the grade for the work falls. At a Gymnasium in grade 9, an index of 3.5 lowers the grade by one third of a grade, and an index of 6.5 by two thirds. The rule applies in every subject, not only in German.