To determine how much prior knowledge affects students' performance on a reading comprehension test, a study was undertaken to examine the prior knowledge factor in a reading competency test developed for college freshmen in New Jersey. The passages used in this test are based on common, everyday topics. Subjects were students in two sections of a basic skills class, both taught by the same instructor and using the same materials as the core program. In addition, subjects serving as the experimental group read supplementary articles related to topics on the test, while subjects in the control group read articles on nonrelated topics. Data were taken from scores achieved on the state-mandated competency test before the students were admitted to college and again during the last week of the basic skills course. To determine if the students were aware of their knowledge about the topics on the test, they were also administered a prior knowledge inventory. Data analysis showed that (1) exposure to the topics did not significantly increase the experimental group's test scores, (2) instruction in basic comprehension skills did significantly increase the scores of both groups, and (3) awareness of topic knowledge did not make a significant difference in scores. (Copies of the prior knowledge inventory, the course syllabus, and titles of the supplementary reading materials are appended.) (FL)