I encountered the following two examples:

  1. Moreover, the proposed scheme is designed in an ID-based setting and so the necessity for certificates and some related problems are eliminated.

  2. Our scheme also achieves setup-freeness and so a user can enjoy the fairness provided by the fair exchange scheme without interacting with the arbitrator for registration.

Is this type of construction (and so) correct? Should there be some commas somewhere? Are they not just two independent clauses joined by and so?

  • 3
    'Should'? Grammatically, they're not necessary. Medically, a comma before the and so 's in the above might prevent people reading out those sentences from fainting, by letting them think it permissible to take a breath. Additionally, the commas would cue for correct analysis (as does your bolding – but that would not normally be appropriate). Jun 12, 2014 at 5:55
  • 2
    A couple of comments about the execrable style manifested in the examples you found: in 1), we have the elimination of "the necessity for [...] some related problems". Presumably, what the writer actually meant was "it is possible to eliminate the need for certificates and avoid some related problems". Sentence 2) suffers from the repetition-infested opaqueness and awkwardness of phrasing that might be expected from a bureaucrat hurrying to finish his assignment so that he can retreat to the canteen for a meal that one hopes will be more digestible than his turgid, stodgy prose.
    – Erik Kowal
    Jun 12, 2014 at 6:45
  • @Erik Kowal Should turgid stodgy prose have a comma? Jun 12, 2014 at 8:10
  • @EdwinAshworth - "No comma?" -- No comment.
    – Erik Kowal
    Jun 12, 2014 at 9:09

4 Answers 4


Please take a look at the sixth definition of and on OALD. The definition states that and can be used to show the result.

Is this type of construction (and so) correct?

In your examples, the two words - and and so - duplicate the presentation of causuality. Semantically, the use of and so is incorrect.

Note that sometimes and so is used not to join two independent clauses.

Judging the beauty of poems and plays is evidently not immediate and so evidently not a matter of taste.


For "correct English", there has to be a comma before "and so" in both of these cases, since an independent clause follows both (ie. if you put what follows "and so" on its own as a sentence, it would make sense grammatically by itself). In any case, it'd surely be understood without the commas, and clarity is the most important thing.


This usage of and so is a more colloquial conjunction than a strictly grammatical one, so in technical or formal writing I would advise against it.

Regarding whether the examples should contain commas: That addition of the colloquial and keeps the clauses clearly independent without resorting to commas. I subscribe to the belief that unnecessary commas should always be omitted, so in these examples I would prefer ", so" but would not add commas if left with the "and so" conjunction as presented.

  • 3
    Are you saying that you genuinely believe and so to be some sort of low-register colloquialism? Seriously? Please provide documented references to support that point, because such an asseveration comes off as outlandish at best and poppycock in the middle, and it only gets worse from there.
    – tchrist
    Jun 12, 2014 at 5:36
  • ... 'such an asseveration comes off as outlandish at best and poppycock in the middle, and it only gets worse from there.' I take it this implies some slight departure from the advice in the Help Center on 'How do I write a good answer?' Jun 12, 2014 at 8:16
  • @tchrist: I didn't say low-register colloquialism. I said this usage is colloquial and not strictly correct. I don't believe this assertion is outlandish, or even terribly insightful for an English grammarian, hence the lack of references. If you believe that is incorrect feel free to present your evidence.
    – feetwet
    Jun 12, 2014 at 13:15
  • 1
    Colloquial is low register on the formality charts. You seem to think there is something wrong with it, that it is “not strictly correct”. But you do not back up that position by citing with any documented evidence supporting it. Without references, it reads like un(der)informed opinion.
    – tchrist
    Jun 12, 2014 at 13:19
  • 1
    @EdwinAshworth Extraordinary claims require extraordinary evidence.
    – tchrist
    Jun 12, 2014 at 13:20

Moreover, the proposed scheme is designed in an ID-based setting, so the necessity for certificates and some related problems is eliminated.

In other words, add a comma then delete the "and". You also need to change the "are" to "is" in this sentence, because "are eliminated" is grammatically incorrect. Because you're referring to "necessity" which is singular, you should write "is eliminated".

  • Hmmm.   I believe that the subject that goes with "xxx eliminated" is "the necessity … and some related problems". Dec 5, 2018 at 4:45

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