Editing: Arranging, revising, and preparing a written, audio, or video material for final production, usually by a party (called an editor) other than the creator of the material. The objectives of editing include (1) detection and removal of factual, grammatical, and typographical errors, (2) clarification of obscure passages, (3) elimination of parts not suitable for the targeted audience, and (4) proper sequencing to achieve a smooth, unbroken flow of narrative. —BusinessDictionary
There are probably a lot of times when running something through Grammarly or even Microsoft Word’s grammar checker will take care of your problems. We ourselves make use of them. They provide a quick way to find things like extra spaces between words. Sometimes Word tells you that a comma is needed, which is not always correct. What you have to understand is that punctuation is also a matter of style and choice. An extreme example is the poetry of e e cummings, who sometimes intentionally dispensed with punctuation altogether.
Contemporary writers tend to avoid using commas as much as possible. On the other hand, lawyers may introduce commas liberally in order to be more precise. Recently the New York Times reported on a lawsuit which hinged on a missing, so-called “Oxford comma.”
In spite of the fact that we are all taught rules for using commas in school, in the actual practice of writing, the rules may be more flexible than you think. An editor can help you make decisions on using them, which really depends on your purpose and perhaps your personal preferences.
I remember when our daughter came home from fourth grade with an F on a “comma test.” As we went over the exam, she expressed dismay at my suggestions as to where the commas should be. “No,” she said firmly, “you put a comma where you take a pause.” She then proceeded to read the sentences aloud, breaking where she thought was appropriate. She made complete sense, but it was different than what the test designer had decided was the correct answer. The point is, the hard-and-fast rules with regards to commas and other matters are often not helpful.
Another reason to use an editor is to insure proper syntax. Syntax means arranging words and phrases into larger phrases, sentences and paragraphs. Grammar checkers cannot do this very well, although they sometimes try to. There are nuances of word meaning that are just not quite right and don’t convey the intended meaning.
A good editor thus makes sure that your grammar and syntax carry through your whole work, including your use of commas.
I have found that many students are confused and helpless when it comes to understanding why a professor, including myself, has accused them of plagiarism. It seems to be a common practice for student writers to find an online article and then copy and paste a sentence into their paper. They often put a sentence from one article in the same paragraph as another one. Sometimes the original articles are cited, but more often not. When we sit down in my office to talk about it, they tell me this was how they wrote all their papers in high school. Some students from outside the US have told both Harvey and me this is how they were taught to write papers.