An attempt to predict reading difficulty with various grammatical measures showed that the relatively crude measure of sentence length is still the most indicative. Yngve's phrase structure measurement and Allen's "sector analysis" were used on 80 selected passages and were compared to the Lorge Readability Formula in terms of tests based on the passages, which were administered to college students. Each of the 80 test lessons were analyzed for 12 predictor variables based on Lorge's concern with hard words, number of prepositional phrases, and sentence length as well as on maximum depth and total storage as determined by both the Yngve and the Allen systems. Yngve is concerned with the nodes and depth of transformational analysis, and Allen deals with levels between sentence and words. Both measures of depth were not as closely correlated to test scores as was sentence length; both the measures of total storage were so closely correlated to sentence length that they were no better as predictors of reading difficulty. Hard words ratioed to depth measures gave less dependable prediction than hard words ratioed to sentence length. Lorge's prepositional phrase count, however, was insignificant as a predictor in this study. References are included. (BT)