Thanks for the question! It forced me to dig a little deeper and investigate this issue.
First off, this question came from GMAT Winners. I have no idea what this company is or how strong these questions are. From looking through their website, and from the troublesome nature of this question, I would say that they are not a trustworthy source of GMAT questions. The worst thing to do is practice with bad questions and that seems to be the case here. So
DO NOT USE THIS QUESTION TO PREPARE FOR THE GMAT!!!JusTLucK04
I am not sure whether it is a valid usage on the GMAT..but I sure have heard " as compared to" quite often...
So per my understanding of what you said...this usage will always be incorrect?
Also the
when usage for comparison in A is incorrect.So A & B both are incorrect options..??
If you can state whats the GMAC's stand on the usage of when?
You are correct that "as compared to" is used and heard often, and it isn't necessarily wrong. It is just wordy. The
MGMAT considers this formulation suspect. I assume that's because there is a more concise way to phrase the idea. In every situation I could think of, and my colleague could think of, you can drop "as" from the sentence. So this formulation is used, but not very concise. You can read more about this
here, specifically the second answer given.
After doing more research, I found that "when compared to" is rarely correct. Most of the time when it is used, it changes the meaning of the sentence. There is the example from that I cited earlier where "when" is used correctly, but more often than not, it makes it sound like the comparison is only true when you compare the two things. Not that the the comparison is true regardless of whether someone decides to compare them or not. For example,
"When compared to a dolphin, a cat is not very smart."
This makes it sound like a cat is not very smart only during the comparison.
It was for these reasons that I started to do some research to find out the source of the question. I discovered that it was from an unreliable source. I couldn't find a reliable correct answer. Some people claimed it was (C) and some claimed that it was (B) neither of these answer choices would be considered correct on the GMAT. We have to consider the comparison words, parallelism, and wordiness when deciding an answer, and no answer choices meet all of this criteria.
The best way to phrase this sentence is as follows, and it is not an option given:
"A new study of old data on roughly 30,000 U.S. children found that children of older fathers have a reduced cognitive ability and an increased chance of schizophrenia or autism compared to children of younger fathers."
Again thank you for your probing questions! I think we can say that we now know a little bit more now, including myself.