Since educators tend not to use the SMOG Grade because of its variant scores from the Fry Graph, and since the SMOG is so easy and requires no word lists or charts, the author decided to attempt a modification of the SMOG so that it might correlate more closely with the Fry Graph.
Smith, L. L. (1984). Using a Modified SMOG in Primary and Intermediate Grades. Reading Horizons: A Journal of Literacy and Language Arts, 24 (2). Retrieved from https://scholarworks.wmich.edu/reading_horizons/vol24/iss2/9