We have a debate on whether it should be "classes" or "classes'" in the sentence below. Your wisdom is appreciated.

Sentence: This rebalancing of customer classes’ impacts on the system means there will be uneven impacts to rates the first year.

For reference, there are five customer classes (e.g. residential, non-residential, etc.) being referenced in the sentence. Thanks for your feedback! Aaron

  • Grammar requires the possessive indicator. Why the question?
    – Kris
    Dec 21, 2019 at 8:33
  • @MikeGraham I don't think a plural makes a good noun adjunct.
    – Kris
    Dec 21, 2019 at 8:34
  • @Kris so... you'd suggest... rephrasing? :P
    – KrisW
    Dec 21, 2019 at 9:21
  • @KrisW There's no question in the post per se. Nothing needs done.
    – Kris
    Dec 21, 2019 at 9:26

1 Answer 1


The quoted example is gramatically correct, but poorly written.

The reason for this, and your confusion, is the word "impacts": it can be read as both a noun (the effects of the thing) and a verb (creates an effect). The sentence, as written, forces your reader back-track and re-parse your sentence to see if "impacts" is a functioning as a verb or noun (apostrophes are easily missed, and often misused).

To prevent your meaning being carried by a tiny punctuation mark, I would suggest this re-wording:

  • This rebalancing of the impacts of customer classes on on the system means there will be uneven impacts on rates the first year.

Note also that one cannot have an impact to something, only on or upon that thing. It's also pretty poor writing to use "impacts" twice in once sentence - "effects" is probably the noun you're looking for for in one of the two cases.

  • Rephrasing is not an answer, though.
    – Kris
    Dec 21, 2019 at 8:32
  • The first sentence of my post is my answer: the possessive apostrophe is needed in the sentence. That answers the OP's question. After that, I try to explain why OP has got themselves into this confusion, and a way out of it.
    – KrisW
    Dec 21, 2019 at 9:19
  • Thank you for your perspectives! I appreciate it!
    – Aaron
    Dec 24, 2019 at 14:39

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