Based on the 4 percent reduction of science and mathematics teachers

My Analysis:

A. Modofier error - Phyllis is not based on 4% reduction. He used 4% reduction as a basis to predict something.
B. The passive construction gives a meaning that something reduced the number of teachers but that's not the intended meaning.
C. Same as B
D. Correct
E. Same as A

Thanks
Harsh

Posted from my mobile device

Based on the 4 percent reduction of science and mathematics teachers over the past year, Phyllis Marcuccio, editor of Science and Children, projects that within the next five years the number of science and mathematics teachers in the United States will have fallen by 35 percent.

(A) Based on the 4 percent reduction of science and mathematics teachers over the past year, - (A) implies that the science and math teachers themselves were reduced. How can you reduce a person?
(B) Last year science and mathematics teachers were reduced by 4 percent, and on this basis - (B) implies that the science and math teachers themselves were reduced. How can you reduce a person?
(C) On the basis of science and mathematics teachers being reduced by 4 percent over the past year - (C) implies that the science and math teachers themselves were reduced. How can you reduce a person?
(D) On the basis of a 4 percent reduction in the number of science and mathematics teachers over the past year, - has no error. hence, (D) is the right answer choice.
(E) Based on last year's 4 percent reduction of the number of science and mathematics teachers, - (E) implies that Phyllis Marcuccio himself is based on the 4 % reduction; this implication does not make any sense.

reduction of - incorrect idiom usage.
Reduction in - correct usage as used in option D.

POE:
(A) Based on the 4 percent reduction of science and mathematics teachers over the past year, --> Incorrect as mentioned above.
(B) Last year science and mathematics teachers were reduced by 4 percent, and on this basis
(C) On the basis of science and mathematics teachers being reduced by 4 percent over the past year
(D) On the basis of a 4 percent reduction in the number of science and mathematics teachers over the past year,
(E) Based on last year's 4 percent reduction of the number of science and mathematics teachers,

GMATNinja VeritasKarishma mikemcgarry

For option A, the official explanations says :
"A. Some would argue that based on … year is an adjectival phrase modifying the noun Phyllis Marcuccio and is therefore incorrect in this context. But current well-established usage allows this phrase to be treated as adverbial, modifying the verb projects. More significant issues arise in the phrase reduction of … teachers.."

I always thought such an expression is a case of misplaced modifier :
Based on the 4 percent reduction of science and mathematics teachers over the past year, Phyllis Marcuccio projects that within the next five years...

It doesn't make sense to say that Phyllis Marcuccio is based on something (4 percent reduction).

The official explanation, however, seems to imply that such uses could be grammatically correct.

Can you please throw some light?

Cheers!
Debo

A,B and C are out as we can reduce the number and not the teachers themselves.

out of D and E - D is a better choice.

That is well established usage of "based on," and I personally have always wondered whether the GMAT would consider it correct in some instances.

Now, here's the thing, I think that structures like that one are not always correct. There's the convention, and there's going too far. Consider the following examples:

Based on the satellite images, it will rain tomorrow.

Based on the data, the trains have been running on time more consistently.

OK, those do not involve the convention to which the above explanation refers.

Neither "it" nor "will rain" are based on anything.

Neither "trains" nor "have been running" are based on anything.

I think the convention works more like what we see in the following example:

Based on the study results, she concluded that the bacterium had mutated.

The sentence does not really make sense, but "concluded ... based on" is sort of like "she based her conclusion on." So, people say "based on, she concluded," and the GMAT has decided to go with it as correct.

That said, I would not be 100 percent surprised if the test went so far as to say that a sentence like the "based on ..., it will rain" or the "based on ..., the trains have been running" is correct. People do use sentences like those, even if they are even more illogical than "based on ..., she concluded.

The key thing to understand is that anything conventional can show up as correct in a Sentence Correction question, even if past Sentence Correction questions seem to have considered that conventional structure incorrect.

Sentence Correction evolves.
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Need a better explanation of why option a) is incorrect. Phyllis's projection is based on the reduction in.......?

Here's (A).

(A) Based on the 4 percent reduction of science and mathematics teachers over the past year,

Notice that this choice does not say "reduction in the number of ... teachers."

It says "reduction of ... teachers."

That conveys the nonsensical meaning that the teachers themselves were reduced, as in shrunk.
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Hi MartyTargetTestPrep
Are there any other obvious errors based on which, we can confidently eliminate answer option 'E'
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Because "Based on last year's 4 percent reduction of the number of ... teachers" uses "of" rather than "in," this version suggests that "last year" engaged in a "reduction of" the number of teachers. Of course, this meaning is nonsensical.
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Here's the official explanation provided by the GMAC for this question:

The given sentence reports that the editor of Science and Children projects a drop of 35 percent in the number of science and mathematics teachers within five years, a projection based on a 4 percent reduction seen last year. Points to consider include the following: Is the modifying phrase based on … year grammatically correct in this context? Is the preposition of with the noun reduction a correct usage? Is reduction … of teachers correct diction?

Option A: Some would argue that based on … year is an adjectival phrase modifying the noun Phyllis Marcuccio and is therefore incorrect in this context. But current well-established usage allows this phrase to be treated as adverbial, modifying the verb projects. More significant issues arise in the phrase reduction of … teachers. The compressed phrasing permits absurd but unintended readings, whereas the intended reading is surely a reduction in the number of … teachers.

Option B: Does teachers were reduced by 4 percent mean that the teachers diminished in stature or status? What is surely be intended is that the number of such teachers decreased, not that the teachers themselves were somehow reduced.

Option C: The phrasing science and mathematics teachers being reduced … year is unnecessarily awkward, wordy, and confusing, failing to convey clearly that the reduction applies to the number of teachers.

Option D: Correct. The phrasing reduction in the number of … teachers is correct. The phrase on the basis of … year is a grammatically and rhetorically appropriate adverbial modifier of the verb projects.

Option E: The preposition of is incorrect with reduction; the correct preposition is in. Some would argue that based on … year is an adjectival phrase modifying the noun Phyllis Marcuccio and is therefore incorrect in this context. But current well-established usage allows this phrase to be treated as adverbial, modifying the verb projects.

The correct answer is D.

Please note that I'm not the author of this explanation. I'm just posting it here since I believe it can help the community.

GMATNinja VeritasKarishma

In few questions the options with Based on are usually eliminated because it wrongly modifies noun and it has a meaning error. Here On the basis of also have a similar meaning wrongly modifying noun. Can you please explain me why On the basis is correct in this case.

regarding choice C.
"on basis of" can go with a noun to make combination "on basis of +noun"
but not all noun can be in this combination. depending on meaning of the noun, the noun can or can not be in this combination.
"on basis of the reduction" is logical
"on basis of existence of this kind" is logical
"on basis of the teachers" is not logical. this is choice C
so, the noun in the combination should show an action, state or phenominon. the noun can not be a physical entity.

Hi manvig, based on... is (what's called) a participial phrase. Since participial phrases act as adjectives, they modify the noun.

On the other hand, on the basis of.... is a prepositional phrase (well, because it starts with a preposition on). When a prepositional phrase appears at the beginning of a clause/sentence, it generally acts as an adverbial modifier. Because this prepositional phrase acts as an adverbial modifier, this prepositional phrase modifies the verb (and not the noun) of the clause that follows this prepositional phrase (why? Because adverbs modify verbs).

Hence, in the correct option (D), the prepositional phrase modifies the verb projects and the prepositional phrase answers the question: How/why does Phyllis Marcuccio project a fall in science and mathematics teachers (remember that Adverbs typically answer the question how, when, where, why, and how much).

p.s. Our book EducationAisle Sentence Correction Nirvana discusses prepositional phrase modifiers, their application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.
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googled " reduction of " and it is mentioned here https://arxiv.org/abs/2007.00377 why "reduction of" is incorrect ?

Based on the 4 percent reduction of science and mathematics teachers over the past year, Phyllis Marcuccio, editor of Science and Children, projects that within the next five years the number of science and mathematics teachers in the United States will have fallen by 35 percent.

(A) Based on the 4 percent reduction of science and mathematics teachers over the past year,

-- 4% in physical size?! Not the intended meaning.

(B) Last year science and mathematics teachers were reduced by 4 percent, and on this basis

-- 4% in physical size?! Not the intended meaning.

(C) On the basis of science and mathematics teachers being reduced by 4 percent over the past year

-- 'being' is incorrect here.

(D) On the basis of a 4 percent reduction in the number of science and mathematics teachers over the past year,

-- Looks good. Keep.

(E) Based on last year's 4 percent reduction of the number of science and mathematics teachers,

-- should be 'last year's 4 percent reduction in the number of'

Answer is D.
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A,B and C are out as we can reduce the number and not the teachers themselves.

out of D and E - D is a better choice due to the meaning clarity.

E should have - reduction in and not reduction of.

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