A study examined the interaction between reading ability and text format. Subjects were 120 sophomores and juniors enrolled in reading methods courses at Montclair State College (New Jersey) who were divided into two equal groups of skilled and unskilled readers by means of a diagnostic reading test. Experimental reading passages based upon college texts of approximately 130 words containing equal amounts of information but systematically varied numbers of arguments were presented in two different formats: standard format text (SFT) and list format text (LFT) in which the standard format text was typographically manipulated so that the information presented in meaningful components, based upon semantic propositions, was separated on successive lines of the page. Combining the variables produced four experimental conditions. Results indicated interactive effects between ability and format for skilled readers, from which it can be inferred that they identify and use cues in the text, but evidence of interactive effects between arguments and ability and arguments and format was not found. The number of arguments did affect comprehension. To improve instruction, teachers, text designers, and text writers should take into account the effects of format and the number of arguments. (JL)