The alphanumeric outline is the standard format most people learned in high school English. Each main heading, or topic, is noted by a Roman numeral and can be separated into two or more distinct classifications. These subheadings would be indented and then noted by a capital letter. The third level of subheadings can be separated into two or more distinct classifications and noted by Arabic numbers. The fourth level of subheadings can be separated into two or more distinct classifications and noted by lower-case letters. Not all headings or subheadings will be separated into further classifications.
Full Sentence Outline
The full sentence outline is similar to the alphanumeric outline in that it follows the same format. The primary difference is that each topic, or thought, is written out as a full sentence. This can be helpful, as it ensures the complete thought is recorded on the outline and will not be forgotten when it comes time to write the paper. It is also helpful because these sentences can be transferred directly to the paper later.
The decimal outline is similar to the alphanumeric outline. The primary difference between is that the decimal outline is written using decimals to note each heading and subheading. The main heading would be noted by a whole number. Each subheading would be noted by a decimal building from the main heading. For example, the main heading would be noted as 1. The first subheading under that section would be noted as 1.1. If there were another level of subheadings, that line would be noted as 1.1.1. The main benefit of using a decimal outline is that each section can be clearly identified back to the main heading. The decimal outline can be written as individual thoughts or in complete sentences.