I tend to make the same set of comments over and over when I proofread
scientific writing, so I thought I'd gather them together into one
place for easy reference.
Updated by Michael L. Littman, 2012, 2014. All rights reserved.
- Comma usage.
- Use a comma after "but", "next", "here", "now", "then", adverbs
etc., when starting a sentence. Then, your text will flow
- If your sentence has one, always use a comma to set off a
leading prepositional phrase.
- Use commas to set off "parenthetical" type phrases, common in
many people's writing, embedded in the sentence.
- As you, I, and everyone else knows, commas are important in
- It is customary to use commas when joining two sentences
together into one, so don't forget.
- Use "which" only after a comma, because it is used to add
descriptive features instead of defining features. So, "the
ball which I threw" should either be "the ball that I threw"
(meaning, "of the many possible balls, I'm talking about the
thrown one") or "the ball, which I threw" (meaning, "that ball
I'm talking about, you might also like to know that I threw
it"). Of all the rules that I have learned, I make a special
effort to follow this one, which I learned from my advisor.
- Avoid using commas for situations not on this list even if you
want to add one because it feels like you want to take a
- Apostrophe usage.
- Pluralize abbreviations using an "s". So, use "MDPs", not
"MDP's" to mean "Markov decision processes".
- Master "its" vs. "it's". "Its" is possessive and "it's" is a
contraction for "it is". So, we say "It's unfortunate that its
nose fell off." In my experience with this rule, it's common
for people to forget its proper usage.
- Clear, direct language.
- Avoid the dangling "this". So, "this example shows that" not
"this shows that". This rule is intended to discourage this
kind of behavior. One hint: Try changing "this" to
"it"---usually, doing so will make it obvious that more context
- To avoid cluttering your sentences, change "in order to" to
- To use simple words when appropriate, change "utilize" to "use".
- Dash/hyphen usage.
- Hyphenate noun phrases if they defy the natural right-to-left
grouping in English. So, "algorithm for reinforcement learning"
is ok, but "reinforcement learning algorithm" should be
"reinforcement-learning algorithm". Noun-phrase hyphenation is
needed to group words in the beginning of a noun phrase, but not
when there are only two words. [A nice example from The Colbert
Report: "Nazi-treasure hunter" (someone seeking Nazi treasure)
vs. "Nazi treasure hunter" (a Nazi who is seeking treasure).]
- Know when to use different lengths of dashes. It is
state-of-the-art usage to employ a short dash (hyphen, single
dash in LaTeX) within words. Ranges require a slightly longer
dash; they are written with a double dash (en-dash) in LaTeX as
explained in pages 14--33 of Lamport's LaTeX guide. To set off
a phrase---something many people do---use even longer dashes
with no spaces before or after them (em-dash, written as a
triple dash in LaTeX).
- Usage related to confusable pairs.
- led/lead. Perhaps because of the pronunciation of the name of
the element "lead", some people are led to believe that the past
tense of the verb "lead" can spelled the same way.
- affect/effect. They are pronounced similarly and they both can
be used as nouns and verbs. It's a recipe for disaster. It
affects the clarity of your writing if you mix up these words.
The end effect is that people are frustrated because they aren't
sure what you said. You can effect change in their affect if
you get it right the first time.
- bare/bear. Bear with me, because you'll want to bring the right
rule to bear. "Bear" can mean the animal or various things
related to the idea of exertion. "Bare" is connected with
nakedness. They seem quite unrelated but sometimes people can
barely tell the difference. I guess you just need to grin and
bear it with your bared teeth.
- it's/its. See 2b. (Or not 2b.)
- dissertation/thesis. The "dissertation" is the document and the
"thesis" is the claim made by the document that the document
supports. Every dissertation should explicitly state its
- their/there. "There" is the answer to "here?" while "their"
describes something an heir might own. Although it's taking
me awhile, I'm starting to warm up to "their" as a singular,
genderless modifier. There is a difference in spelling between
these words and it's important to be able to distinguish their
usage. (Suggested by Morgan McGuire.)
- hear/here. "Hear" is what you do with your ear and
"here" is the answer to "There?" (See 5f.) Around here, we
don't like to hear about people misusing these
words. (Suggested by Morgan McGuire.)
- shear/sheer. When someone cuts your hair with a shear,
make sure your ear is safe, and sheer
pleasure is so pure as to make you go "ee!". If misusages were
fleece, you'd want to shear them off for the sheer joy of
being right. (Suggested by Morgan McGuire.)
- fair/fare. The verb "fare" means to go or travel, the noun "fair" is a
festival, and the adjective "fair" denotes a lack of bias. Did
you fare fairly well in your understanding of this example?
(Suggested by Morgan McGuire.)
- one- vs. two-word phrases. These phrases should be one word when
used as a noun and make up two words when used as a verb.
More: follow up, followup; speed up, speedup; set up, setup; in
line, inline; make up, makeup.
|We trade off time and energy
||to strike a careful tradeoff.|
|We cut off any runs
||that went beyond the 10% cutoff.|
|We print out the data and pick up
||the printout later from the pickup box.|
|I will write up my experiment
||and then send the writeup to my supervisor.|
- Paper structure.
- Don't use citations as nouns. Say "As explained by Kearns and
Singh (2002)" or "As explained in the literature (Kearns and
Singh 2002)" instead of "As explained by (Kearns and Singh,
2002)". This rule is summarized
and Cohn (2001), along with many others that I've included.
- Don't use latin abbreviations. That is, say "that is" instead
of "ie" or "for example" instead of "eg". I guess I don't mind
Latin if it's spelled out, for example "ad hoc". But, no one
seems to use "exempli gratia" (e.g.) and "id est" (i.e.), for
example, because they seem unnecessary, that is, there are
perfectly good English substitutes.
- Avoid empty sections. Some text is needed between a section
title and the first subsection of the section.
- Capitalize names of structural items like sections, equations,
figures, and tables, as in "Section 3.1". So, "next section",
but "Section 6". The same rule applies to "Item 2", "Table 3",
"Assumption 4", and "Theorem 1.5".
- Don't begin a sentence with a variable or function name. It can
help to put "The equation ..." in front of it first.
- Put punctuation after an equation, especially if it ends a
- Every paragraph, section, paper, chapter, and dissertation
should have a topic sentence.
(Littman style guide. Littman grammar rules. Littman comments.
Littman usage. Littman style file. Littman seems to think he can get
Google to search his own files better than he can.)