The parallelism that we want here is between CONTRACTORS PAY and ARE PAID. We can omit a helping verb only when it "carries" to both parallel elements:

The letters are stamped and (are) mailed.

In this example, both of our parallel elements had the same helping verb, so we can drop it from the second element. In this sentence, though, we can't drop ARE, because there is no helping verb in the first parallel element. It's just the simple present tense verb PAY. So without ARE, the parallel elements would be CONTRACTORS PAY and PAID. This doesn't work.

As for the other place where ARE is a helping verb - THAN STATUTORY EMPLOYEES vs. THAN ARE STATUTORY EMPLOYEES - this isn't really a parallelism issue. It's a meaning issue with comparisons. The comparison that we want to make is: Independent contractors are paid less consistently than statutory employees (are paid). Here, though, no meaning is lost by omitting the verb (or part of the verb) in our second element.* If no meaning is lost, we can omit the whole verb (as in B) or part of the verb (as in D).



A. This makes 3 elements parallel: PAY, ARE PAID, and THEY MAY. Not only is this a grammatically bad parallel structure (we shouldn't reintroduce the subject "they"), but from a meaning perspective, these are not comparable elements. The 3rd one should be in contrast to the first two.

B. Correct parallel elements & comparison, good contrast, and an independent clause after the semicolon. CORRECT

C. PAY and PAID are not parallel

D. Correct parallelism & comparison. Here, there's a bit of a meaning issue with using "in addition" rather than a contrast word such as "though" or "however." We want to contrast these ideas, not connect them.

E. PAY and PAID not parallel

*sometimes there is a meaning issue in omitting the verb. See an example here: https://www.beatthegmat.com/comparison-q ... tml#578243

Hey Wondering,

Everything you wrote is correct, the only caveat is for this one:

It is possible also to change the time via parallelism:

Independent contractors are paid less than statutory employees were (paid)

As written, that sentence isn't correct, because the change in tense is illogical. You'd need some meaning aspect of the sentence to require a tense change. I'd have to add some time markers to make it work:

Independent contractors are always complaining about their wages, even though they're paid more now than statutory employees were paid ten years ago.

Ceilidh, can you do it without throwing in "now" "ten years ago" kind of stuff?

-t

Hm, that's actually a very good question.

If the subject is the same in each comparison, that could certainly work:
Independent contractors are paid more than they were.
From a meaning perspective, though, I think we need indicators of time such as "now" or "ten years ago." I don't think that's actually a grammar requirement, though; it's just a meaning one. Comparisons don't always have to have the same verb tense if we're comparing things across time.

If the subjects are different, as in the example here - Independent contractors are paid less than statutory employees were - I think the same idea applies. But with two different subjects, it seems even more important to establish context words. Or if you were writing an essay, we'd know from the rest of the context that we're comparing time as well as people, so this would work.

So again, I'm pretty sure that it works grammatically, but it's missing information meaning-wise.

That said, I can't think of a single example where this idea is tested on the GMAT. They usually don't get too subtle with these kinds of distinctions.