Public speaking texts urge speakers to organize their message in order to increase their audience's comprehension of it. Tests were run to determine if listeners understand better when three message organization variables are employed in a speech: explicit statement of the central idea, explicit statement of the main points, and transitions before and after main points. Eight versions of a speech, in which these variables were present or absent in various combinations, were prepared. Students listened to one version and then took a multiple-choice comprehension test on the material. The results showed that understanding of the speech did not improve significantly when these variables were present. It is suggested that operational definitions of "central idea" and "main points" be improved. (JK)