In this B2 exercise the student had to complete the second sentence so that it had a similar meaning to the first sentence, using the word given in block capital letters. The student must not change the word given and they can only use between two and five words in the space.

36. ‘Sometimes tiredness causes the machine operators to make mistakes.


Sometimes mistakes …………………………………………… the tiredness of the machine operators.

A student of mine wrote

“Sometimes mistakes ARE CAUSED BECAUSE OF the tiredness of the machine operators.”

The textbook, published by Cambridge, says the following are the correct solutions

possible answers to Q36

36 are made OR occur/happen | because of

I understand that Cambridge solutions work better, but I'm not sure why my student's solution is wrong. Is caused and because in the same sentence redundant? And yet, the Internet has many many examples of sentences containing the string: “caused because (of)”

Googling yielded these examples:

  1. More specifically, the operator should be held strictly liable when environmental damage is caused because of a malfunction in the operation of the activity or when the damage is caused by an accident. Official Journal of European Communities

  2. The physical phenomenon Condensation is caused because the air in the room contains a certain amount of steam which can come from various…

  3. No sustainable and avoidable damages shall be caused because of service works

  4. This situation may be caused because of the dimensionality of the feature vectors.
    EEG Analysis Techniques and Applications

  5. Symptoms are caused because of too much stomach acid and include: Acid reflux;...
    University of Rochester Medical Center

  6. Seasons are caused because of the Earth's changing relationship to the Sun.

  7. Sadly, more than a year later and Stephanie is dealing with the aftermath of the virus. It’s what she calls an onslaught of symptoms that were caused because of the virus.

I suggested that the following worked better without "because" and that the preposition by was necessary.

Sometimes mistakes ARE CAUSED BY the tiredness of the machine operators.

However, can someone please explain why the student's solution was inappropriate.

  • 5
    As so often, the question appears to be more about the beliefs of the person who set the test than the answer. I can find no fault with the answer given, although I prefer caused by to caused because. In short, it's somebody's view of the correct answer when half a dozen other answers are equally correct. Mar 19, 2021 at 18:39
  • "If mistakes are caused because of " is redundant, so are the answers the publisher gives.....because of is due to. For me, by goes to agency. And because of goes to the reason. And are made for me is the basically the same as are caused, here.
    – Lambie
    Mar 19, 2021 at 19:54
  • @Lambie the supplied answers "Sometimes mistakes occur / happen because of the tiredness...." doesn't sound redundant to me.
    – Mari-Lou A
    Mar 19, 2021 at 19:57
  • 2
    I have been trying to find an example of "caused because of" in well-written text, and while I have found a bunch in peer-reviewed medical papers, they were all written by non-native speakers as far as I can tell. I did find "Crews are currently on the scene working to get power up and running again, but are also looking to see if any damage was caused because of the outage." (source) but I wouldn't consider most news blurbs to be worthy of emulating.
    – ColleenV
    Mar 19, 2021 at 20:01
  • 1
    @ColleenV Thinking hard about caused because of. What if the cause is indirect, as in: Several injuries were caused that day because of the argument you provoked. Or; The trouble was caused because of your dog Mar 20, 2021 at 1:21

4 Answers 4


Most people won't mark someone as a non-native speaker if they wrote "caused because of"—it's something that is pretty commonly heard when people are speaking and composing their thoughts as they talk. It's not well-written English though.

"Caused" is defined as "to make something happen". "Because of" is defined as "as a result of". So, if I say "Heart attacks are caused because of blood clots." I'm literally saying "Heart attacks are made to happen as a result of blood clots." That isn't really what I'm trying to communicate, even though most people will infer what I mean from the context.

Blood clots cause heart attacks.
Heart attacks are caused by blood clots.
Heart attacks happen because of blood clots.

When you say "caused because of", you're trying to use the "happen" part of "caused" without the "made to" part or make "because of" mean "by" instead of "as a result of". You should just write "happened because of" or "was caused by".

The Google Ngram viewer results for 'is caused because of,is caused by,happens because of' show “is caused by” is much more common than either 'is caused because of' or "happens because of'.

Google Ngram viewer chart of “is caused because of,is caused by,happens because of”

The results for * because of are also interesting. The top results for the word immediately prior to "because of" seem to show that "because of" is most often used either on its own, or with 'is' or 'was':

  • and because of
  • not because of
  • but because of
  • is because of
  • was because of

chart of '* because of' results

  • 1
    Wow! Impressive analysis. Thank you!
    – Mari-Lou A
    Mar 26, 2021 at 20:15
  • You're welcome! Ngram results always require a grain of salt, but I know you can handle it :)
    – ColleenV
    Mar 26, 2021 at 20:33

The impression given by "are caused because of" to me is that of a typical 15 year old writer (native speaker), who is trying hard but ultimately is producing a rather wordy expression.

The repetition "caused because of" seems typical of student essays.

Nevertheless, as your research shows, it may be poor style, but is quite common. This is a good case for giving constructive feedback, and not just marking "correct" or "wrong".

This is correct but wordy. A better answer would be "are made because of"

  • Telling an 18 year-old Italian student that Cambridge did not include their solution because it is "wordy" doesn't help them understand. I suggested that "cause" and "because" shouldn't be used in the same sentence but I'd like to hear other users' opinions.
    – Mari-Lou A
    Mar 19, 2021 at 19:53
  • Sorry, but that is the answer. Style is complex. I wouldn't expect an 18 year old native speaker in Cambridge to understand any better.
    – James K
    Mar 19, 2021 at 20:45
  • 1
    I'm sorry, I don't understand the analogy, The 18 year old in question is an Italian speaker and this question is from a simulation (mock) English language exam they going to sit this very Thursday, the results of which are important for their university entrance. Cambridge is both the publisher of the textbook and the exam board.
    – Mari-Lou A
    Mar 19, 2021 at 20:52
  • 2
    The exam is irrelevant to me. This isn't the English Exam Candidates stack exchange. This is the English Language Learners. The point I make is that this kind of expression is very common, and very "natural" but not very "good". There are better ways to express this idea using the word "because", and Cambridge have given some examples. But native speakers don't always write "good" English. So this is an opportunity for useful constructive feedback.
    – James K
    Mar 19, 2021 at 20:58

Strictly speaking it's redundant, yes. It adds another indirection: "It is caused because of", nominally, explains the cause for the cause. As an example, her mother telling her so caused the girl to go shopping; that in turn may have been caused by the grandmother telling the mother: "The girl's shopping run was caused [by the mother telling her so] because the grandmother told the mother."

But in everyday language such redundancies are quite common ("I don't know nothing") and typically interpreted in a pragmatic way, by applying context and common sense. It is still, as others remarked, bad style.

In this particular case the redundancy is more conspicuous because of the "cause" in "because". The sentence "The fire was caused because of this switch" sounds terrible; but "a fire was prevented because of this fuse" we can perhaps live with, although it is redundant in quite the same fashion (a fire was prevented by this fuse).


Sometimes we cannot see the wood for the trees. The long question has sprouted a forest in this case.

Sometimes mistakes ARE CAUSED BECAUSE OF the tiredness of the machine operators.”

Now with Because of already inserted as a given. Let us do some simple substitution

Sometimes mistakes ARE "make something happen" BECAUSE OF the tiredness of the machine operators.”

We can then see that this makes no sense

If we used the noun Cause then it would read

Sometimes mistakes ARE "reason" BECAUSE OF the tiredness of the machine operators.”

We can then see that this also makes no sense

We do not need to make something happen, we have already implied that something is going on we just need to finish the phrase "Sometimes mistakes ...." which could be happen/occur or are made.

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