What is the most effective way to distinguish main points in an outline?

Using Roman Numerals to distinguish main points in an outline is effective because they establish a clear hierarchy and organization, which is essential in outlining. Roman Numerals represent major ideas, allowing a reader to quickly identify the primary points of the speech or presentation. This method creates a visual distinction that helps in navigating complex material and facilitates better understanding of the structure of the content being presented.

While numbers and letters can also organize information, they might not visually convey the same level of formality or clarity in distinguishing major points. Bullet points provide a different formatting approach that emphasizes lists or series but may not effectively indicate the hierarchical nature of main points as Roman Numerals do. Thus, using Roman Numerals enhances the clarity and organization of an outline, making it easier for both the speaker and the audience to follow the argument or narrative.