Results show that SMOG’s Grade predictions have a correlation of 0.66 with
the original Grades against RI’s 0.78. It can easily be observed that SMOG
overestimates Grade. SMOG is based on the average number of complex words per
sentence. With the SMOG formula, texts with at least 1.01 complex words per sentence
get a Grade of at least 10. Among our 33 test-texts, 23 (70%) have value greater than
1.01 for the parameter of complex words per sentence. So 70% of our test-texts are
given a Grade of either 10 or 12 by the SMOG formula.