Is the construction "noun- and adverb adjective noun" correct?

Example: "we found a significant difference between human- and algorithmically generated summaries".

  • 1
    the technical term for this is a suspended compound. Just for your information and to improve the question. For example, high- and low-pressure turbines.
    – Lambie
    Sep 3, 2018 at 17:14
  • Or chemical- and excrement-based fertilizers. Suspending the modifiers like that does nothing to clarify that you are drawing a comparison between two very different things, summaries generated by humans and summaries generated by algorithms.
    – TimR
    Sep 3, 2018 at 17:42

2 Answers 2


This is a question about suspended compounds:

like: short- and long-term interest rates or second- and third-class tickets. The adjective can be a past participle too: funded- and unfunded-pension plans. There is a space after the first dash.

human- and animal-generated waste. [just to show the dashes]

When you have two nouns, both of which are connected to the past participle, you need two dashes with a space after the first one.

Therefore, I would write your phrase like this:

human- and algorithm-generated summaries

You do not need an adverb. The noun algorithm works just fine.

Summaries generated by algorithm=algorithm-generated summaries.

  • What is to prevent someone from understanding that hyphentated modifier as meaning "summaries where humans and algorithms cooperated"?
    – TimR
    Sep 3, 2018 at 15:53
  • 3
    @Tᴚoɯɐuo: that would be human-and-algorithm-generated summaries, not human- and algorithm-generated summaries. Sep 3, 2018 at 15:57
  • 3
    +1 The use of suspended hyphens with multiple adjectives is a very commonly used and recognized stylistic device, acknowledged by almost every style guide and grammarian. In an answer of my own, I would quote The Chicago Manual of Style, but here is a quick website. Sep 3, 2018 at 16:22
  • Let us continue this discussion in chat.
    – Lambie
    Sep 3, 2018 at 17:06
  • Whoever insists on downvoting this is doing a disservice to the OP.
    – Lambie
    Sep 4, 2018 at 17:14

We found a significant difference between human- and algorithmically generated summaries.

That sentence invites that unnatural awkwardness upon itself. It could be easily avoided:

We found a significant difference between summaries generated by humans and those generated by algorithms.

There is no reason to reject such a sentence on the grounds that it repeats a word or phrase, whereas this concoction human- and algorithmically generated is something of a monstrosity.

So take your pick, a bit of repetition or a train-wreck of a modifier.

P.S. Let me add that this rejection of a phrase because it is repetitive is a bugbear of programmers especially, and there are quite a lot of them on this site. They should not apply their peculiar sense of parsimony to natural language.

P.P.S. And let me also add that you will find this sort of hyphenated combination in the wild. I don't dispute that it is grammatical. But I do think it is crappy writing. It does absolutely nothing to enhance clarity—in fact it does the opposite—and there is no real justification for it.

  • The adverb is de trop and in English, it is very common to have a noun+two past participles with dashes. It couldn't be "more English", as it were. It's a bit much to say monstrosity. Not nice when people are trying to learn something.
    – Lambie
    Sep 3, 2018 at 15:47
  • @Lambie, I don't dispute that you could find many such unnatural modifiers. But I disagree that it couldn't be more English. It could. As Saint Paul said, not all that is grammatical is idiomatic.
    – TimR
    Sep 3, 2018 at 15:49
  • I wish the downvoters would give their reasons. I sense it is simply that they don't like my criticism of that modifier on stylistic grounds, but they cannot think of a decent justification for using such a modifier.
    – TimR
    Sep 4, 2018 at 16:42
  • I am somewhat shocked by your assertion of level of English studies and this question. It is very common in academic writing, and is also seen in better quality magazines like The Atlantic Monthly. It is quite prevalent in economics and finance. However, it is not something one sees as much in litcrit circles.
    – Lambie
    Sep 4, 2018 at 16:55
  • @Lambie: That it is common does not mean it is stylistically good or justifiable. It only means that it is grammatical, a licit choice. I am shocked that you are not understanding the distinction.
    – TimR
    Sep 4, 2018 at 16:57

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