The American Psychological Association developed a standardized paper format in 1929 in order to create easier reading with fewer distractions due to differences in style. Following these guidelines with items in a list or series not only helps your paper conform to APA standards, but also illustrates the relationships among ideas.
Numbers
According to the Publication Manual of the American Psychological Association (6th edition), for ideas that need to be enumerated in a specific order, such as steps in a procedure or to indicate importance, use Arabic numerals followed by a period for each point: 3. Type complete sentences after each number, capitalizing the first word in the sentence and placing proper end punctuation after each item. Begin a new line with each subsequent number, indenting 1/2 inch from the left margin.
Bullets
If numbers seem inappropriate because you do not want to indicate a specific order to the ideas in the list, use bullets instead of numerals. Select a plain type of bullet, such as squares or circles. As with Arabic numerals, begin a new line for each new concept in the list, start with a capital letter and end with proper punctuation, writing in complete sentences for each entry. If you submit your finished paper for publication, the publisher may change the type of bullet to the standard for the particular journal.
Within Sentences
You may want to emphasize seriation within a single sentence, as well, which requires a different format. Use lowercase letters enclosed in parentheses to separate such items: (a). Do not capitalize the words that follow these letters unless they are proper nouns. To add further emphasis, you may use bullets such as circles or squares, which will place each concept on a separate line. Punctuate as grammatically and syntactically appropriate, placing a comma or semicolon at the end of each item in the series.
Structure
Properly structure each item in the series to create smooth reading. Place a comma between items in a list unless there are commas within the items. In that case, use semicolons to separate the larger ideas. For instance, "Tom, the butcher, Joe, the baker" represents four people, but "Tom, the butcher; Joe, the baker" represents just two. Create parallel structures, using the same grammatical format for each item in the list. For instance, you might start each with an -ing word or use subject-verb-object structure.