Prior to the development of this vaccine, meningitis and pneumonia wer

OFFICIAL EXPLANATION



THE PROMPT

• Meaning?
Meningitis and pneumonia were much more common among Navajo and Apache children than [meningitis and pneumonia were common among] other children in the United States.
• Tracking on the comparison
→ first, don’t get discouraged. Parallelism in comparisons is one of the most difficult subjects in SC.
→ second, take note of the way that I used brackets in the sentence above.
-- from those brackets, you can see that the items under comparison are the frequency of the diseases in one group of children and the frequency of the diseases in another group of children.
-- “frequency of disease in one group of children” = frequency of the diseases among those children. (The first among is given to you; I’m just showing you how the comparison language works.)

• among Navajo and Apache children, other children in the United States were more common than meningitis and pneumonia? No.
• stated differently (and just as absurdly): other children in the U.S. were more common among Navajo and Apache children than meningitis and pneumonia were common among Navajo and Apache children? No.
Wrong comparison. See my analysis beneath the prompt.
• Also, I wrote [were common] in brackets at the end of this option.

→ As is true of many comparisons on the GMAT, we have an elliptical construction.
→ If you have no idea or only a vague idea what I am talking about, see my recent post on ellipsis, substitution, and parallelism, which you can find by clicking here.
ELIMINATE A


• I see no errors
• Now we are correctly comparing frequency of disease among one group of children with frequency of disease among another group of children
KEEP


• the verb is does not stay parallel with the non-underlined verb was
• watch the verb tenses. The mismatch between was and is is fatal.

ELIMINATE C


• do not use comparison words such as compared to in sentences that also use comparative structures such as more . . . than.
→ the comparison structure more . . .than already indicates comparison.
→ saying “compared to” in this sentence is redundant
ELIMINATE D

• Same problem as that in option D
→ do not use comparison words such as in comparison with in sentences that use more . . . than
ELIMINATE E

The correct answer is B

COMMENTS

Did you all know that crickets can tell you the temperature?
I like cricket song, which happens to be very . . . chirpy . . . at the moment.

The U.S. Library of Congress explains how to use crickets to find the temperature here. Scientific American's version is here.

Here is my question: which human being sat there counting cricket chirps, comparing them to the temperature, and figuring out the pattern?
Ingenious.

Kudos go to those who explained. Have a good rest of your weekend, and please be safe.