When writing and speaking, native speakers generate and tolerate a very low frequency of errors
Evaulation of student production in a foreign language tolerates a relatively high frequency of errors.
If the frequency of erorrs reaches certain (high) levels, meaning and communicative efficiency fall off, leading to non-communication and gibberish.
To determine the error ratio:
Example
Total number of words in essay = 243
Number of mechanical errors = 56
Error ratio: 243/56 = 4.3 (one error for each 4.3 words)
Grade (mechanical errors) = D
Scale for assigning letter grades based solely on the frequency of mechanical (or sometimes even logical) errors.
The scale is based upon the number of errors present with respect to the total number of words produced.
Ratio Note Ratio Note 15 A+ 9 C+ 14 A 8 C 13 A- 7 C 12 B+ 6 C- 11 B 5 D+ 10 B- 4 D 3 D- 2 F