Persuasive messages about a complex political issue were constructed in various ways of manipulation of three message variables: Source Label (Republic/Neutral), Amount of Use of Slogan (No Slogan Repeat/Slogan Repeat), and Format (Question-Answer/Straignt Descriptive). These produced eight message versions. The purpose was to determine if changes in any of these variables would influence either attitude change toward the issue or comprehension of the message among voters who read messages containing the same content and arguments. Printed brochures with the eight message versions were used in a field survey of a statewide sample of registered voters in Ohio, 300 in the experimental group and 50 in the control group. The messages concerned state support of education by the 1969 Ohio legislature. Subjects were interviewed to determine demographic characteristics, past voting behavior, and pre-reading attitude toward the issue. The experimental group read one of the eight message versions. A seven-question multiple choice test on facts of the issue was administered to both groups; those in the experimental group also received a post-reading attitude test identical to the pre-reading test. The messages used produced favorable attitude change at a significant level, producing positive change in 51% of the sample. The amount of a message that was read had a significant effect upon comprehension. (Author/DB)