Of the 100s of K – 12 teachers I have worked with over the years, only a small handful could explain how to use commas correctly. To no surprise, of the 100s of adult continuing education students I have taught over the years, most were confused by commas.
I finally wrote Zen Comma because I couldn’t find a comprehensive, clear, and credible resource dedicated to commas. The rules for commas make sense, but my experience suggests that people generally don’t understand the core principles of commas use and, therefore, have difficulty using them correctly.
On the other hand, once a person fully understands the principles for commas, the rules will make sense. As stated in Zen Comma, page 1,”Commas are visual clues that have only one purpose: Help the reader separate parts of sentences into discrete, meaningful messages.”
For example, consider commas before coordinating conjunctions (e.g., “and,” “but”). Following the principle that commas separate and identify individual meanings within sentences, we use a comma to separate individual independent clauses, and we leave out a comma to indicate that an idea is not yet complete (Zen Comma Rule D).
The following two correct examples show how this principle affects comma use.
1. “I left Susan a message last week but haven’t heard back from her yet.”
Here, we don’t use a comma before “but” because the second part must be connected to the first part for the sentence to be grammatically and conceptually correct. This sentence has a compound predicate (i.e., one subject with two verbs). A comma before “but” would separate the subject from its second verb, yet they must be connected to indicate a complete thought. However, by leaving out the comma, we indicate that the verb “have heard” is connected to the subject, which is in the first part of the sentence. Without a comma, the subject is correctly linked to its second predicate.
2. “I left Susan a message last week, but I haven’t heard back from her yet.”
Here, we use a comma to indicate that the second part is a separate thought. The comma indicates that one message is complete and that another is about to start.
Commas with Short Sentences
This same principle tells us that “I swam and she called for help” is incorrect, or, at least, doesn’t follow comma principles. The second half of the sentence is a separate thought and has its own subject and verb. With strict adherence to the principle, the correctly punctuated sentence is “I swam, and she called for help.” The comma tells the reader that the first idea is complete and that another is about to start.
(People who follow a more relaxed application of the rules may leave out the comma in this sentence because it is short. However, consider whether a comma would help identify the two messages in this short sentence: “Dogs like running and jumping is good for them.” My advice regarding short compound sentences: If you use the comma sometimes for clarity, use it all the time for consistency.)