Common Writing Errors

This page collects several of the most common writing errors that I have noticed in papers, reports and theses. Many are related to incorrect translation from German (or other languages) to English.

See also: Get it Write

And see also “How to Write Good, by Michael O’Donoghue ;-)


Never say "allows to" again

Never use the expressions "allows to", "helps to", "requires to" etc. Each of these expressions requires a direct object.

Wrong: "This allows to easily spot errors."

Right: "This allows us to easily spot errors."

Wrong: "These debuggers help to solve difficult problems."

Right: "These debuggers help developers to solve difficult problems."


Citations are annotations, not parts of speech

Wrong: "Feeblevetzers were introduced in [1]."

Right: "Feeblevetzers were introduced by Martin [1]."


"Who" vs. "which" and "that"

Who refers to people. Which and that refer to groups and things.

Wrong: "We identify developers that have the appropriate expertise."

Right: "We identify developers who have the appropriate expertise."


"Which" vs. "that"

Use that for restrictive clauses (i.e., restricting what is referred to) and which for non-restrictive clauses. The acid test is: if you can remove the clause and it still makes sense, use which, otherwise use that.

Wrong: "This is shown in the following method that is invoked by the interpreter."

Right: "This is shown in the following method, which is invoked by the interpreter."

(You can remove the whole "which ..." and it makes sense.)

Wrong: "We call the equivalent parts which describe the same feature ‘building blocks’."

Right: "We call the equivalent parts that describe the same feature ‘building blocks’."

(You cannot remove the qualifying text.)

Note that many authors confuse "which" and "that", but there is a clear semantic difference. Consider the two following statements:

  1. You should write a PhD thesis, which will further your academic career.
  2. You should write a PhD thesis that will further your academic career.

Both are grammatically correct, but the first states that writing any PhD thesis will further your career, whereas the second suggests that you should write a particular kind of thesis that will be good for your career. Note that a comma is needed to introduce the non-restrictive clause.

Caveat: Actually it is common in English to use "which" instead of "that" also for restrictive clauses, as in:

  • You should write a PhD thesis which will further your academic career.

(Note the absence of the comma!) In many cases this will cause no confusion, but wherever it might (like here), it makes good sense to maintain a clear distinction and use "which" only for non-restrictive clauses.

See also: Which or That?


No comma before "that"

In German, you must put a comma before "dass". Not in English.

Wrong: "The log message confirms, that comparing pthread with == is not portable."

Right: "The log message confirms that comparing pthread with == is not portable."

Basically, use commas in English only if leaving them out would lead to ambiguity.


Don’t join sentences with commas

In German you can join clauses with commas; in English you must make them separate sentences, or you may join them with colons ( : ), semi-colons ( ; ), dashes (—), or conjunctions (and ...).

Wrong: "RetroVue is another commercial back-in-time debugger, it implements the most common functions."

Right: "RetroVue is another commercial back-in-time debugger; it implements the most common functions."

This is also known as a comma splice.


"Amount" vs. "number"

"Amount" refers to an indiscrete quantity; "number" refers to a discrete quantity.

Wrong: "Testing can take a long time, depending on the amount of differences between versions."

Right: "Testing can take a long time, depending on the number of differences between versions."


"Less" vs. "Fewer"

Use "less" for indiscrete quantities and "fewer for discrete quantities.

Right: "Fewer people will consume less beer."

See also: http://oxforddictionaries.com/words/less-or-fewer


"Little" vs. "few"

"Little" refers to size; "few" refers to number.

Wrong: "The programmer only has to do little, but necessary, steps."

Right: "The programmer only has to do few, but necessary, steps."


"Its" vs. "it’s"

It’s really simple: "it’s" = "it is"; "its" is possessive.

Wrong: "If its void, then there are no versions committed yet."

Right: "If it’s void, then there are no versions committed yet."


"A" vs. "an"

Use "a" if the first letter of the following word is pronounced as a consonant.

Wrong: "A historical view of an UML diagram is better than a XML document."

Right: "An historical view of a UML diagram is better than an XML document." Note the pronunciation, which is what counts:

  1. "An istorical view" [NB: Americans might prefer "A historical view" after all.]
  2. "a yoo-em-ell diagram"
  3. "an ex-em-ell document"

Avoid Nounification

Avoid using the substantive form of verbs if you want to describe an action.

Wrong: "The composition of the toolbar is done like this ..."

Right: "The toolbar is composed like this ..."


Run time, runtime and run-time

  • run time – noun, the time at which the system runs
  • run-time – an adjective describing something which exists at run time
  • runtime – noun, the run-time support, e.g. the VM

”Run-time errors are caught by the runtime at run time.”


Software — countable or uncountable?

Software should be used as a mass noun (uncountable noun), like hardware. However, it is gaining countability in specific contexts. Think of it like paper: you can say "Paper is recyclable" (mass noun) or "Here is a new paper" (countable). "Software" has no plural form, though.


Get the "Lead" Out

This is a surprisingly common error. The past tense of "to lead" is "led", not "lead". [The word "lead" that sounds like "led" is a gray metal that has nothing to do with leading."

Wrong: "These changes have lead to improved performance."

Right: "These changes have led to improved performance."


"Such that" vs "so that"

"Such that" means "to the extent that" ("my grammar is such that it is beyond reproach") while "so that" means "in order to" ("I study grammar so that I am beyond reproach"). Don’t confuse them.

Wrong: "The tasks are decoupled from each other, such that they can be executed concurrently."

Right: "The tasks are decoupled from each other, so that they can be executed concurrently."


Last changed by cc on 6 April 2017