To develop more accurate population forecasts, demographers

Hello Everyone!

Let's tackle this question, one issue at a time, and come up with the correct choice! First, let's take a quick look at the original question, and highlight any major differences between the options in orange:

To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

(A) have to know a great deal more than now about the social and economic
(B) have to know a great deal more than they do now about the social and economical
(C) would have to know a great deal more than they do now about the social and economical
(D) would have to know a great deal more than they do now about the social and economic
(E) would have to know a great deal more than now about the social and economic

After a quick glance over the options, we see a few places we can focus on:

1. have to know / would have to know
2. now / they do now
3. economic / economical

Let's start with #3 on our list: economic vs. economical. This is an easy way to eliminate 2-3 options because it's a common mistake we see on the GMAT:

economic = dealing with the economy
economical = inexpensive, cheap, thrifty, etc.

Since the sentence is talking about the economy, we can eliminate options B & C because they use the word "economical," which isn't the correct word for this sentence. That was quick, right?

Let's move up to #2 on the list: now vs. they do now. Here are the remaining sentences with the non-underlined parts added in to better catch any problems:

(A) To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

This is INCORRECT because it creates a non-parallel comparison. We are supposed to compare what demographers would have to know (knowledge) to what demographers know now (knowledge). This is comparing what demographers would have to know (knowledge) to now (time), which isn't parallel!
(This is also wrong because "have to know" isn't how to write a conditional statement. "Would have to know" is a condition, which would make this a conditional statement.)

(D) To develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the social and economic determinants of fertility.

This is CORRECT! It compares what demographers would have to know (knowledge) to what they know now (knowledge), which is parallel! It's also best to use "would have to know" to indicate this is a conditional statement, and it does that correctly!

(E) To develop more accurate population forecasts, demographers would have to know a great deal more than now about the social and economic determinants of fertility.

This is INCORRECT because it creates a non-parallel comparison. We are supposed to compare what demographers would have to know (knowledge) to what demographers know now (knowledge). This is comparing what demographers would have to know (knowledge) to now (time), which isn't parallel!

There you have it - option D is the correct choice! Even if you weren't confident on how to deal with conditional statements and verb tenses, you could still answer this question by focusing on parallel comparisons and proper word usage!


Don't study for the GMAT. Train for it.

To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

(A) have to know a great deal more than now about the social and economic
(B) have to know a great deal more than they do now about the social and economical
(C) would have to know a great deal more than they do now about the social and economical
(D) would have to know a great deal more than they do now about the social and economic
(E) would have to know a great deal more than now about the social and economic

The question tests the concept of Modifiers, Comparison, and Conditional sentences.

“To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.”
We can identify three points in the question that need to be examined.
When we do a vertical scan of the options, we see that two options begin with “have to know” and three options begin with “would have to know”.

Two options end in ‘economical’ and three options end in ‘economic’.

Two options have the phrase “more than now” and three options have the phrase “more than they do now”.

The choice between ‘economic’ and ‘economical’ is simple. The word ‘economic’ is the adjective form of the word ‘economy’ and is the better choice in this sentence because the sentence discusses the “social and ….. determinants of fertility. The word ‘economical’ means avoiding waste or extravagance. It doesn’t fit into the sentence.
On this basis, we can eliminate Options B and C.

To choose the best among Options A, D, and E, we can either use the rule of the Conditional sentence by choosing between the phrases ‘have to know’ and ‘would have to know’, or the rule of Comparison by choosing between the phrase “more than now’ and “more than they do now”.

Let us start with the rule of Comparison. The comparison should be between how much ‘demographers’ know now and how much the ‘demographers’ should know. The comparison will be complete only when the noun demographers is mentioned again or a pronoun is used to refer to them.
“demographers have to know a great deal more than now”

“demographers would have to know a great deal more than they do now”
It is only in the second construction that the comparison is complete.
On this basis, we can rule out Options A and E.

The Conditional sentence starts with ‘if’. However, in this sentence, the condition is conveyed through the prepositional phrase “To develop more accurate population forecasts”.
The construction of a conditional sentence is as follows:
If + subject + verb in the past tense, Subject + would/could + verb in the present tense.

If demographers wanted to develop more accurate population forecasts, they would have to know a great deal more than now about the social and economic determinants of fertility.

In this sentence too, that construction has to be maintained to make a proper conditional sentence. On this basis, Option A can be ruled out.

Therefore, Option D is the most appropriate option.

Jayanthi Kumar.

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that in order to develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the determinants of fertility that are related to social and economic factors.

Concepts tested here: Meaning + Tenses + Comparison

• The "would + simple present tense verb" construction is used to refer to hypothetical future actions and habitual actions in the past.
• Comparison must always be made between similar elements.
• The simple present tense is only used to indicate actions taking place in the current time frame, indicate habitual actions, state universal truths, and convey information that is permanent in nature.

A: This answer choice incorrectly uses the simple present tense verb "have" to refer to a hypothetical future action; please remember, the "would + simple present tense verb" construction is used to refer to hypothetical future actions, and the simple present tense is only used to indicate actions taking place in the current time frame, indicate habitual actions, state universal truths, and convey information that is permanent in nature. Further, Option A incorrectly compares "know" to "now"; please remember, a comparison must always be made between similar elements.

B: This answer choice alters the meaning of the sentence through the phrase "social and economical"; the use of "economical" incorrectly implies that to develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the determinants of fertility that are inexpensive; the intended meaning is that to develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the determinants of fertility that are related to economic matters. Further, Option B incorrectly uses the simple present tense verb "have" to refer to a hypothetical future action; please remember, the "would + simple present tense verb" construction is used to refer to hypothetical future actions, and the simple present tense is only used to indicate actions taking place in the current time frame, indicate habitual actions, state universal truths, and convey information that is permanent in nature.

C: This answer choice alters the meaning of the sentence through the phrase "social and economical"; the use of "economical" incorrectly implies that to develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the determinants of fertility that are inexpensive; the intended meaning is that to develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the determinants of fertility that are related to economic matters.

D: Correct. This answer choice uses the phrase "economic and social", conveying the intended meaning - that to develop more accurate population forecasts, demographers would have to know a great deal more than they do now about the determinants of fertility that are related to economic factors. Further, Option D correctly uses the "would + simple present tense verb ("have" in this sentence)" construction to refer to a hypothetical future action. Additionally, Option D correctly compares "know" with "do".

E: This answer choice incorrectly compares "know" to "now"; please remember, a comparison must always be made between similar elements.

Hence, D is the best answer choice.

All the best!
Experts' Global Team

A more accurate population forecast does not exist now. A forecast exists, but it is just as accurate as it is now - it is not more accurate than it is now. Developing a more accurate forecast is a hypothetical situation - it may or may not be possible to develop more accurate forecasts. The outcome depends on another hypothetical situation: the demographers would have to know more. It may or may not be possible for the demographers to know more. Hence the statement is hypothetical and not factual.

However if we already knew that it is possible for the demographers to have more accurate knowledge and in such case more accurate forecasts could be developed, we would not then require "would" - in that case the statement would be factual and grammatically correct without "would". However we do not have a grammatically correct option without "would" ( A wrong - comparison issues , B wrong - use of economical). Hence option D is the best.

OA is D.

Q41 - OG12:
Verb form; Logical predication
Th is sentence explains a hypothetical situation and therefore calls for a conditional—or contraryto- fact—construction, because in order to more accurately predict population, demographers would have to know more than they presently
know. A present-tense verb is required to describe the current state of demographers’ knowledge, and the comparison made by the sentence must be
between current and conditional knowledge, not between knowledge and time of knowing (now). A Wrong comparison—between knowledge and time (now); conditional verb is needed. B Conditional verb is needed; economical is the
wrong adjective. C Economical is the wrong adjective. D Correct. Conditional knowledge, indicated by would have to know, is correctly compared
to current knowledge. E Wrong comparison—between what demographers need to know and now.

The correct answer is D.

D

AB: would establishes meaning better elim these two choices.

C: economical is inappropriate here. means inexpensive
E: same economical is inappropriate here. means inexpensive

please check out this link https://www.english-test.net/forum/ftopic4710.html

I'd go with (D).


This is future conditional, so I would eliminate (A) and (B) since they do not have "would".

I would eliminate (E) because of the faulty comparison. Comparing "know a great deal" and "now" is not apples to apples.

Your remaining choices are identical except for economic v. economical. Economical sounds weird to me in this context, so I'd go with (D).

@ Bibli

Even a casual look at the choices will prove E as a wrong choice. There is no need to entertain any doubt about the inappropriate and absurd use of the word economical in the context. Rather, you must evaluate the topic first and eliminate unfit ones.

Secondly, look at the following post.

to-develop-more-accurate-population-forecasts-demographers-54658.html -- 18 posts

It contains at least 18 posts on these topics and there are at least another five posts that run up to another 30 posts . In spite of all these, do you still want a new discussion?. The same thing will hold good for your other posts, which have all been thoroughly discussed in the pages of this forum. Please remember you have to look before you leap and search before you script

Dear sunny91,

I'm happy to respond.

My friend, many student labor under the misconception that one can arrive at GMAT SC mastery by memorizing some mythical "complete" set of grammar rules. This rule-based approach to the GMAT SC is doomed to failure. Yes, there are some important rules, and it's important to know those--for example, SVA. Nevertheless, many patterns in language are much more complex and demand broad intuition about the language. The only way a non-native speaker develops this intuition is through the habit of reading. See:
How to Improve Your GMAT Verbal Score

I would say that any rule you have learned about the use of "would" is almost virtually useless, as this word has a bewildering multiplicity of uses.

One use is in the subjunctive, in a contrary-to-fact statement, the word "would" expresses the consequences in this contrary-to-fact world. Your first statement is an example of this.
1) If I had $10M, I would buy a luxury car. = correct statement in the subjunctive

Another correct use involves somebody's speculation of a future possibility. Your second statement is correct in this sense:
2) The scientist believes that such a machine would be wonderful. = also 100% correct

Another use is as the future tense from the perspective of a speaker in the past, when using sequence of tenses.
3) By the summer of 1824, Beethoven felt that he had said all he wanted to say in symphonic form, but that he still would have more to say in the string quartet format.

Another use, admittedly somewhat less likely to show up on the GMAT, is as an expression of preference, often considered gracious and polite.
4) I would be interested to find out more about your trip.
5) Would you please tell me about this book that you you reading?

All five of these are 100% correct. It's very hard to make a simple rule for "would."

Does all this make sense?
Mike

Hi rajathpanta,

The scientist believes that the machine would be wonderful --> is incorrect because here we are mixing present with conditional.

Why is this so? because it is a rule. For conditionals there a few rules and you have to just remember them, there is not much to understand here. The rules on Conditionals are governed by set rules. MGMAT has explained the rules quite well, just make a note of them.

Consider this sentence: The scientist said that the machine would be wonderful. --> here "would" is expressing past as it is being used in the reported speech. The sentence is correct as per another rule on the usage of would.

The scientist believed that the machine would be wonderful - Correct usage, "would" expresses future from the past point of view.

Hope that helps,

Vercules

Hi rajathpanta,

In my last explanation I did not discuss hypothetical would, but a few rules related to would. I guess that you are confused because you are not able to find any conditional construct in the question above. The hypothetical would is used based on the context of the sentence. In almost all the questions which test standard conditional constructs "if then" constructions are used.

See the below question from OG12 which uses the conditional if x happened, then y would happen.

Q 67) Affording strategic proximity to the Strait of Gibraltar,.......

In the question above hypothetical conditional would is used. The sentence expresses a hypothetical situation, which needs a hypothetical conditional would. But, the incorrect answers are incorrect for different reasons, other than the use of would.

The question does not really test your knowledge on conditionals if you solve it by POC. The following question will also have the correct answer as (D). I have just made a change in option (D) ( "would have to" to "have to")

To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic detriments of fertility.

(A) have to know a great deal more than now about the social and economic
(B) have to know a great deal more than they do now about the social and economical
(C) would have to know a great deal more than they do now about the social and economical
(D) have to know a great deal more than they do now about the social and economic
(E) would have to know a great deal more than now about the social and economical


Correct choice is (D) because other options are wrong for clear grammatical and contextual errors; Although, "would have to know" will be better because the hypothetical situation is being discussed

The same conditional is tested in the following OG question;

Q 16) Retail sales rose 0.8 of 1 percent in August,
intensifying expectations that personal spending.....

I hope the above explanation helps,

Vercules

To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

A. have to know a great deal more than now about the social and economic - Since it is a hypothetical situation, a conditional clause must be used. Economic is correct
B. have to know a great deal more than they do now about the social and economical - Hypothetical Situation + Economical is wrong
C. would have to know a great deal more than they do now about the social and economical - Would Have is correct. Economical is wrong.
D. would have to know a great deal more than they do now about the social and economic - Correct
E. would have to know a great deal more than now about the social and economical - Illogical Comparison between knowledge and Time (Now). Economical is wrong

Economic - Is used to refer to general general economy
Economical is used for cost wise reference. E.g. Product X is economical (not economic)

I will choose D

social and economic --> economic means related to finance ---> intended meaning

economical -thrifty ---> changes the meaning of the sentence --> making the fertility sound economical

A is clear OUT

D is left.

Ooh... now we're getting deep!

In the "pure" Anglo-Saxon system, the "conditional mood" does not exist because there is no inflected conditional mood. Idem for "future tense." What we call "future tense" and "conditional mood" are actually composed tenses from, respectively, the present and past forms of modal verbs.

However, neither of the two statements you proposed is actually a "conditional" statement. The second simply expresses factual belief about the future ("it will work"); the second refers to a future that is posterior to his belief but may well be anterior to the present moment; this is why we use the past tense form of "will" ("it would work"), also known as past posterior. The expression of his belief does not hinge on any condition.

In the case of this problem, however, we are dealing with a conditional statement, since the development of more accurate forecasts DOES depend on a condition (whether demographers can gather more information).

Whether the "if [present] then [present/future]" qualifies as a hypothetical conditional depends on the perspective and semantics. In this case it is clearly a conditional. The use of the present in the then-clause would make no sense, because while present tense can imply futurity in some cases, here we contrast this futurity to what they know now, so we would need another word (the "will") to "kick" it into the future.

Therefore, in answer to your question, it would not be correct to write: "To develop more accurate population forecasts, demographers have to know a great deal more than they do now about the social and economic determinants of fertility." It would be correct to write, "To develop more accurate population forecasts, demographers will have to know a great deal more than they do now about the social and economic determinants of fertility."

This does, of course, imply a slightly different angle than does the correct answer D. D suggests that this is idle, parlour game hypothesizing, whereas the sentence I just wrote reads as an instruction or a prescription.

Dear sunny91,

I'm happy to respond. The difference concerns whether the future item is viewed as a sure thing or is speculative.

Case I: future event is viewed as factual and certain
present:
1) The general believes that the enemy will attack from the south.
past:
2) The general believed that the enemy would attack from the south.
There, "would" is just the past tense of "will." In both cases, the general was viewing the attack as something guaranteed to to happen, from his point of view. Since #2 is in the past, it might be followed by a factual statement of what actually did happen.

Case II: future event is hypothetical or contrary-to-fact.
present:
3) The general believes that the enemy would attack from the south.
That sentence is correct, but it provokes the question: why doesn't the enemy attach from the south?
This might also appear with an explanatory conditional:
4) The general believes that the enemy would attack from the south if it can cover all that ground in such a short time.
In other words, we are expecting the result if the condition is met, but overall, we are still doubtful that this condition will be met.

It's much harder to talk about what was hypothetical in the past. I guarantee that the GMAT will not be interested in testing that.

Once again, I cannot emphasize enough how much the habit of reading can help with dozens and dozens of questions of this sort. Once you develop intuition for all these words in context, much will become clear. I recommend that blog linked in my previous post.

Does all this make sense?
Mike

I believe either of the following would work:

Peter would have to know more about driving than he does now.

Peter would have to know more than he does now about driving.

However, repeating the phrase would be a fatal case of redundancy:

Peter would have to know more about driving than he does now about driving.

Would also be interesting to see other comments.

Hi jabhatta2,

Ellipsis isn't just about whether words that we need in one part of the sentence exist elsewhere in the sentence. Instead, it's more about whether omitted words can be understood from the way the sentence is structured. This means that we may omit words that are there in the sentence or we may omit forms of those words (or even words that aren't there in the sentence). This can't be done randomly though, and whether a reader can understand what has been omitted plays a major role in deciding whether the omission is possible.

In this case:
1. The GMAT goes with the "They would have to know a great deal more than X" interpretation, where X is now. "They would have to know a great deal more than now" isn't as clear as D, so this is a good reason to remove E.

2. If we go beyond (1), I'd be happy with ellipsis in a sentence like this:
(2a) In 20 years, the Earth will be hotter than now.

This is a shorter way of saying "In 20 years, the Earth will be hotter than (it is) now". I think that the sentence is clearer with it is than without, but I'd try to look for other splits first.

Option E, however, is different. In (2a), "The Earth will be" and "it is" are very similar (is is a form of be). In option E, the verb in the first half is would have to know, whereas what we want in the second half is just know. This is why the do in option D is important. This type of do can help us shut other verb forms (like would) out so that we can reach inside the infinitive and grab that know.

That said, I can't say whether the GMAT would agree with this analysis, so it's probably better to stick with (1) as a reason to remove E.