Commas, list, including Oxford - Graduate Writing Center

Nested Applications
GWC - list including oxford

Commas, List, Including Oxford


A list consists of three or more grouped items: “bread and cheese” is a grocery list but not a grammatical list; “bread, cheese, and pickles” is both.

When constructing a list, place a comma between each item:

Variables analyzed in the regression included population size, GDP, third-party assistance, and number of previous endogenous conflicts.

That last comma—the one before the “and” (or “or”) that precedes the last item in a list—is known as the “Oxford” or “serial” comma. Ironically, perhaps, the Oxford comma is less frequently used in British English than American, and it is technically optional, provided you’re consistent within a given document.

Better safe than sorry

That said, leaving out the Oxford comma can potentially generate confusion (and chuckles) in your reader. Take, for example, this sentence:

This thesis is dedicated to my parents, Professor Chakrabarty and Professor Moustakas.

Did your parents advise your thesis?

The slip in meaning arises here because the comma is overworked: we could read this sentence either as a list with no serial comma or as apposition—a construction in which something is renamed. Compare this version, which clears things up:

This thesis is dedicated to my parents, Professor Chakrabarty, and Professor Moustakas.

Now it’s certain that we’re looking at a list.

Always including the Oxford comma is a useful way to minimize ambiguous list constructions and reserve that precious brainpower for other writing-related conundrums.

But wait

The Oxford comma is not a silver bullet for preventing ambiguity, however:

This thesis is dedicated to my kids, Sylvia, Hart, and Ezra, as well as my parents.

Are Sylvia, Hart, and Ezra the children here, or are they some other people this author wanted to thank? Again, are we looking at an appositive or a list?

In cases like this one, it can be useful to supplement commas with dashes or semicolons or other structural markers, which can clarify the boundaries between list items:

  • This thesis is dedicated to my kids—Sylvia, Hart, and Ezra—as well as my parents.
  • This thesis is dedicated to my kids; to Sylvia, Hart, and Ezra; and to my parents.

Finally, consider simply rearranging the list items:

I went on a walk with my dog, Lewis, and his sister.

Unless you’re packing multiple leashes and plenty of doggy bags, we’ll probably want this version:

I went on a walk with Lewis, his sister, and my dog.

Lists vs. Nested Pairs

One particularly common comma error is treating a nested pair as a list:

Chapter I explains the research problem, methods, and discusses relevant literature.

This sentence is not a list; rather, it contains a pair of verbs (explains and discusses), one of which distributes to a pair of direct objects (research problem and methods). These pairs should each be treated in the usual way—connected with “and,” with no commas:

Chapter I explains the research problem and methods and discusses relevant literature.

In constructions like this one, writers might be tempted to retain the comma before the second "and": "explains the research problem and methods, and discusses relevant literature." But, for the same reason, this comma, too, is unnecessary.

Conclusion

As with any other construction, achieving clarity in your lists requires being attuned to possible misreadings and quashing them with punctuation, restructuring, and the rest of your syntactic toolkit.

List Commas Links

GWC - all topics list heading

Writing Topics A–Z


This index makes findings topics easy and links to the most relevant page for each item. Please email us at writingcenter@nps.edu if we're missing something!

A-Z content menu

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q R  S  T  U  V  W  X  Y  Z

A

abbreviations

abstracts

academic writing

acronyms

active voice

adjectives, compound

advisor, selecting and working with

AI

apostrophes

appointment with GWC coaches, how to schedule

argument

article usage

artificial intelligence

assignments, understanding them

audience

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B

body paragraphs

booking an appointment with a GWC coach

brackets, square

brainstorming

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C

capitalization

citations

charts

ChatGPT

citation software

citation styles

clauses

clarity

clustering

coaching, about

coaching, how to schedule

colons

comma splices

commas, FANBOYS

commas, introductory

commas, list

commas, nonessential / nonrestrictive information

commas, Oxford

commas, serial

common knowledge

commonly confused words

compare-and-contrast papers

compound adjectives / modifiers

concision

conclusions

conference presentations

conjunctive adverbs

coordinating conjunctions

copyright and fair use

critical thinking

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D

dangling modifiers

dashes

dependent clauses

dependent marker words

display equations

distance learning

double submission of coursework

drafting

Dudley Knox Library

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E

editing your own work

editing: outside editors

em dash

en dash

equations

exclamation points

executive summary

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F

FANBOYS

FAQs

figures

first person, use of in academic writing

footnotes

fragments

free-writing

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G

generative artificial intelligence (AI)

gerunds

grammar

graphics

graphs

group writing

GWC appointment, how to schedule

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H

homophones

Honor Code, NPS

human subjects research

hyphens

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I

ibid.

incomplete sentences

independent clauses

Institutional Review Board

interviews, conducting

introductions

IRB

iThenticate

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J

Joining the Academic Conversation

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L

LaTeX

library liaisons

lists, syntax of

literature reviews

logic and analysis

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M

M dash

making a GWC appointment

mathematics

memos

methodology

modifiers, compound

modifiers, misplaced

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N

N dash

nominalizations

note-taking

noun clusters

numbers

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O

organization

outlining

Oxford comma

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P

paragraph development

parallelism

paraphrasing

parentheses

parts of speech

passive voice

periods

persuasion

phrases vs. clauses

plagiarism, how to avoid

plagiarism-detection software

plain language

polishing

prepositional phrases

prepositions

pronouns, clarity with

pronouns, grammar of

proofreading

publishing

punctuation

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Q

questionnaires, administering

questions

quotation marks

quoting

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R

Reading with Intent I

Reading with Intent II

redundancies

reference software

reflection papers

research

research guides, discipline-specific

research questions

restrictive vs. nonrestrictive information

reusing papers

reverse outlining

revision

roadmaps

run-on sentences

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S

scheduling a GWC appointment

self-citing

semicolons

sentence fragments

serial comma

signal phrases

significance

so what?

source blending

sources, engaging with / critiquing

sources, evaluating the reliability of

sources, citing

spelling

standard essay structure

STEM / technical writing

Strategic Reading I

Strategic Reading II

style

subject–verb agreement

subjects, grammatical

subordinating conjunctions

summarizing

surveys, administering

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T

tables

teams, writing in

technical writing

tense

that vs. which

thesis advisor, selecting and working with

thesis process overview

Thesis Processing Office (TPO)

thesis proposals: common elements

thesis statements

thesis writing

this, that, these, those

tone, professional

topic sentences

transitions

types of papers

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U

United States or U.S.?

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V

verbs and verb tense

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W

which vs. that

why write?

writer’s block

writing in groups / teams

writing process

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Z

Zotero

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