I've seen here that there is no plural of expertise, so what should I do in the following sentence?

the different expertise is/are complementary.

To put into context, we have a multidisciplinary consortium with partners of different "expertise" (or maybe skills is a better word)

Stated more generally, can a "mass noun" be a subject? If yes, can I put the verb in plural to show that it is used as a plural?

From your answers, it looks like I should completely reformulate my sentence. Should I really avoid this?

3 Answers 3


You could say you employ people within different areas of expertise, or people with varying skill sets.

Your example phrase lacks a bit of context, but I could imagine it flowing somewhere around these lines, including the notion of expert(ise) and skill sets in one sentence:

When you decide to hire the services of our experts, their wide variety of skill sets is complementary.

  • thank you for the quick solution provided. I like the "varying skill set". However, I would like to know if/how I can use my sentence (or a similar sentence in another context)
    – radouxju
    Jan 24, 2014 at 7:14
  • @radouxju I added a suggestion to my answer
    – oerkelens
    Jan 24, 2014 at 7:25

Here's my recommendation: Use expertises. Don't be confused by what you've read in that thread.

You've managed to come up with a sentence where expertise needs to be pluralized. You are talking about two or more distinct kinds of expertise that complement each other.

I have no problem with:

In order to perform well in this job, the manager needs expertise in management, programming, scheduling, and testing. These different expertises are complementary.

If you're not bold enough to pluralize expertise, you can get around the problem by saying:

In order to perform well in this job, the manager needs expertise in management, programming, scheduling, and testing. These different kinds of expertise are complementary.

Some times ago, there was a similar debate on ELU about the plural of equipment. In that case, the debate got rather heated, because the user didn't provide any legitimate example construct where equipments might be a better word.

As one extra note to those who remain unconvinced, who stand ready to click the downvote button: Ignore those red squiggly lines from your spell-checker! There is ample precedent. Read on:

Often in putting together a new combination they lack specific expertises, and in the pressure of competition they do not have time to develop them in-house.
(from the book The Nature of Technology: What It Is and How It Evolves, by W. Brian Arthur, 2009)

These four expertises – that of the educator, the political orator, the judge, and the general – oversee aspects of that moral life itself, which the statesman regulates overall.
(from the book Reason and Emotion: Essays on Ancient Moral Psychology and Ethical Theory by John Madison Cooper, 1999)

There is even one book – ironically entitled Rethinking Expertise – that begins by defining a "Periodic Table of Expertises":


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  • Thanks for the detailed answer. Altought the use of "skill sets" from @oerkelens was a good workaround, this is the type of answer I was looking for.
    – radouxju
    Jan 24, 2014 at 10:40
  • This is a well-researched and explained answer but I would argue that "areas of expertise" is much more common than "expertises". Jan 24, 2014 at 12:34
  • @starsplusplus - You would get no argument from me. The start of my third sentence ("You've managed to come up with...") was meant to indicate that this is a relatively rare case – which, when you think about it, makes this question all the more interesting.
    – J.R.
    Jan 24, 2014 at 14:20
  • Sorry, I wasn't clear. I meant that it would be more common to use "areas of expertise" in a sentence like this ("the different areas of expertise are complementary"). Are you saying "areas of expertise" can't be used here? If so, please explain. Jan 24, 2014 at 14:23
  • @starsplusplus - No, I'm not saying that "areas of expertise" can't be used, or shouldn't be used here – there's not enough context to know for sure which wording would be best. Based on how the O.P. asked the question, though, I assumed that "expertises" would be the better word to use, but the O.P. was reluctant to do so, because, "there is no plural of expertise, so what should I do?" My answer refutes that erroneous assertion, saying, "Yes, there is a plural of expertise, and, if that's the best word to use, then by all means use it." However, I wouldn't use the plural word very often.
    – J.R.
    Jan 24, 2014 at 19:33

You are right. The word expertise is a mass noun.

Expertise (mass noun) - expert skill or knowledge in a particular field.

You can say:

Services by experts from different areas/fields/domains are complementary.

If you want to use expertise anyhow:

The service from the expertise from different domains is complementary.

  • Or, the O.P. could just use expertises. See my answer.
    – J.R.
    Jan 24, 2014 at 10:23

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