Public Health Official: After several years of vaccinating all of the

Great question Mike! My only query is - Would this really be a 600-700 level question, or is it closer to a 700 & above kind of question? Your thoughts? Thank you again!

Dear vishnuns39620,
To be honest, one of the hardest things for me to estimate is the difficulty level of a question I write. Once I write a question, the solution is obvious to me, so that makes it relatively hard to determine its objective difficulty. When we enter questions such as this into the Magoosh product, the computer tallies the cumulative results, and over time that's how we determine the difficulty level of a question, similar to the way GMAC determines difficulty through releasing experimental questions.
When I enter any question on GC, the system, by default, requires me to enter a difficulty level, so basically, I am just taking my best guess --- I often guess conservatively, the lower of two choices. I could see an argument for 600-700 level or for 700+ level. I would be very interested to hear what other users say about the difficulty of this question.
Mike

Hi Mike,

How can we be so sure that the disease will definitely arrive for young childrer.

The word "will" is very strong in option A.

Thanks,
Jai

' If the authorities stop the vaccinations, then the children born after that time will be without any protection against this highly infectious disease. '

Mike,

I'm a bit confused about this statement. I agree to everything you say but then I don't feel the above statement is necessarily true. For example Smallpox: we don't do vaccines for smallpox anymore because it's not there anymore. Isn't it?

Then how can we say that kids are at risk when the population has been completely vaccinated?

Dear gauravkaushik8591,
I'm happy to respond.

We have to make an important distinction here.

The human race was able to stop vaccinating against small pox because we had been doing it for so long that the disease was declared eradicated everywhere on earth. They stopped administering the small pox vaccine in 1979 when it became clear that there were absolutely no cases of the disease remaining anywhere on the planet. That's why we don't get small pox, even though since 1979 folks have not gotten vaccines for it --- there is absolutely no left from whom we could contract the disease.

Worldwide eradication is the exception, not the rule, in the history of disease. Besides small pox, the only other disease that has been declared eradicated is Rinderpest, a disease that affected cattle and other ungulates. In other words, small pox is the only human disease ever to be eradicated worldwide. Of the 10,000s or 100,000s of diseases that humans can get, this is the only one ever to be eradicated.

Essentially, you are taking the exception and considering it the rule. We are explicitly told in the prompt: "Our state imports meats and produce from countries with high incidences of diseases for which our country has vaccines." We don't know which diseases, but it's certainly reasonable to assume that Tacitus' Disease, a "highly infectious disease," is flourishing somewhere else in the world. In other words, to assume worldwide eradication, you are assuming a 1/100,000 exception took place in this case. We don't know where Tacitus' Disease is active --- maybe it's in the countries from which we import food --- but it must be active somewhere. It would simply be unreasonable to assume that it wasn't.

Does all this make sense?
Mike

Hi Mike,

I have been your keen follower.
The above question is of the 650-700 level.I just wanted to understand in a bit detail about how GMAC actually fixes the level of the question.I mean is it through some sort of Percentile analysis related to that question.

Thanks for responding in advance.

Regards,
KB

Dear karna2129,
I'm happy to respond.

First of all, please understand: any difficulty estimates given here in GMAT Club are complete guesses, pure estimates. Invest them with absolutely no validity whatsoever. I wrote this particular question, but is it a 650 question? a 700 question? To be perfectly frank, from the question itself, I have no idea. Absolutely no one can look at a question and predict with complete precision the level of difficulty of a question.

Now, for this particular question, I happen to know that since we released it in our product in Magoosh, almost 2000 Magoosh users have answered it, and approximately 44.7% of them have answered the question correct. Now, are Magoosh users a good estimate of the entire GMAT taking population? I don't know. I do know that when GMAC tests experimental questions, it gets tens, even hundreds, of thousands of responds: by comparison, fewer than 2000 responses is a relatively small sample.

Let's assume that, of all test takers, 44.7% of them got the question correct. Well, looking at the GMAT percentiles:
https://magoosh.com/gmat/2013/gmat-score-percentiles/
If 44.7% get the question right --- that's a percentile that corresponds to about a 560 GMAT score. This is a rough idea. One might call this a "560-question," although that is problematic.

Notice, that even with a great deal of numerical information, the upper reaches of the percentile information become very tricky, because even when people are randomly guessing on five-choice multiple choice, they still have a 25% chance of guessing correctly. If only, say, 3% of the population can actually compute the answer to a question, this small percentage will be hard to separate from all the random guesses who simply, by pure chance, happened to guess correctly. One needs some very sophisticated statistical analyses to make discerning distinctions in that upper part of the Bell Curve.

Keep in mind --- this entire idea of attaching a particular point value to a question is highly suspect, at a number of levels. Notice that GMAC itself doesn't even touch this with a ten-foot pole. GMAC has absolutely no interest in assigning point values to questions, because it's such an inherently dubious business. It's one of these ideas to which student attach considerable importance without fully understanding how logically shifty it is, so we folks who work for private companies and answer student question have to discuss it, and in doing so, we convey the mistaken impression that the entire idea holds any water at all. It's an idea that has gained a great deal of currency, not because it's inherent sound, but only because students mistakenly imagine that such information is critically helpful to them. In any teacher-student relationship, ideas that arise primarily on the student side rather than the teacher side overwhelmingly tend to be considerably less helpful in the long run to the students than they might have imagined. Just because an idea is popular doesn't mean it's good!

For example, suppose one gets this question and questions as hard as this correct, and suppose one gets, say, a 27 on Verbal. Well, as you well know, a 27 on Verbal could be paired with a 15 on Quant or with a 51 on Quant --- those different Quant scores would have virtually nothing to do with one's verbal abilities, but would result in vastly different GMAT scores. If we start comparing difficulty on Verbal vs. Quant questions, we are comparing apples to oranges, because different segments of the population excel at these different tasks. Furthermore, one's GMAT score is not at all a simple thing to understand: the GMAT uses a mind-bogglingly difficult algorithm in the Computer Adaptive Testing, and those of us without Ph.D.s in Psychometrics could not hope to understand all the nuances, even if we were allowed to see the process they are using. (In fact, that entire algorithm is proprietary knowledge of GMAC, and those of us on the outside know nothing about it!) One's GMAT score in fact depends both on the difficulty of the questions one gets correct and the difficulty of the questions one gets wrong: that's part and parcel of how the CAT calculates your score. If one gets all the questions of this difficulty correct, vs. half of them right and half of them wrong, those two scenarios would result in very different scores. Performance on one question, in isolation, is virtually meaningless. See:
https://magoosh.com/gmat/2012/what-is-th ... tive-test/

I would say: a discerning approach would be to abandon any thought of attaching particular GMAT-scores to particular questions. Through keeping a log of your own mistakes, get familiar with the patterns and with what is hard for you. Knowing your own weaknesses is considerably more important than knowing overall statistical trends.

Does all this make sense?
Mike

Hi Mike,
I call upon your wisdom once more.
I see that the answer is A, as it's the most likely one.
My questions is, why do we eliminate D?
According to the health official, "Our state imports meats and produce from countries with high incidences of diseases for which our country has vaccines. "... I agree that he's not listing the disease, but can't we infer this?
Also, since he is referring to food, but only to imported food, and not saying that the food produced inside the country can carry the disease, doesn't this actually tell us that that's not the case?

Dear ronr34,
I'm happy to respond.

First of all, notice that (D) is extreme. "No food products" --- none at all! This would be false even if only one odd product out of 10,000 had some traces of one virus or the other. It's very hard to conclude something so extreme. In general, on GMAT CR and RC, beware of all-inclusive statements --- it's very hard to infer that such statements are true.

It seems more or less reasonable to infer that homegrown food products are, on average, safer than the imported food products. It seems more or less reasonable to assume that the incidence of viral infection is far less for these homegrown products, but to infer that they are 100% safe and entirely pure, completely virus free --- that's a bit too much. That's very typical of a wrong answer pattern on the GMAT CR --- take something otherwise perfectly reasonable, and make extreme so that it's no longer reasonable.

Also, technically speaking, we know zilch about the homegrown food. The Public Health Official seems very concerned about imported food from places with high incidence of the disease, but technically, he doesn't make any comparison at all to food grown in the state, and any comparison is completely implicit. Even if (D) were not so extreme, it still would not have the character of a good GMAT inference, because there is a way that we are guessing in the dark. If something is not mentioned at all, either in the positive or the negative, we are on much less sure grounds when we make any inference about it.

A good GMAT inference or conclusion we can draw is something absolutely unambiguous, something which we can conclude with absolutely no doubts. If something wasn't even mentioned, we can have doubts.

Does all this make sense?
Mike

the answer to this question seems to be assuming something. no where in the passage we have been told that the vaccination of Tacitus' Disease is for "children" !! the passage has talked about "vaccinating all of the citizens of this state for Tacitus' Disease" ------> this does not mean that we need to vaccinate just the "children" . who knows that this particular vaccination of "Tacitus' Disease" is administered to only ADULTS !!!!
though is selected A;however i feel that A should have read as: citizens of the state will be at risk for Tacitus' Disease

Dear aditya8062,
My friend, this is a subtle thing about the GMAT CR. You don't need to have the detailed knowledge of a topic that only a specialist would have --- in this case, only, say, the detailed knowledge of a molecular biologist who studied vaccines. That's the kind of outside knowledge that you absolutely don't need. BUT, you do need to have general outside knowledge, the kind of knowledge that most adults would have and take for granted. See:
https://magoosh.com/gmat/2014/gmat-criti ... knowledge/
Here, it's absolutely essential that you have the kind of knowledge about vaccines that virtually every parent in the industrialized world has, and that any pediatrician would tell you: almost all vaccines are given in early infancy. If there's any risk at all that children could get the disease, then of course we would want to inoculate them as soon as possible. The only vaccines I know that are given in adult life are (a) those that children would be quite unlikely to get (e.g. Hepatitis C, a risk for drug use and unprotected sexual relations), or (b) something that needs to be updated regularly in a booster shot (flu, tetanus). The passage clearly indicates that children would be susceptible to these diseases, and it doesn't even mention the issue of booster shots. If children are vulnerable to the disease, why on earth would any responsible medical professional delay the vaccine until adulthood?

The GMAT CR loves to prey on folks who think that CR questions depend on absolutely no outside knowledge of any kind, including any obvious real world fact. If your imagination and critical thinking runs in directions that are not supported by the real world, this tendency will pose a problem in the GMAT CR, in your B-school application, and in your work as an MBA in your career. Read that blog article for suggestions.

Does all this make sense?
Mike

Great question Mike. I do have some doubts about answer choice A even though it seems to be relatively correct. I believe we are not supposed to make assumptions on CR questions unless specifically asked to do so. Also, not resorting to outside knowledge is advised. When you say " people who are vaccinated can carry the virus, but they simply don't get sick from it. In all likelihood, the vast majority of members of this population are passive carriers of the virus" isn't this an assumption you're making based on extrinsic knowledge rather than deducing it from the premises itself? The statement is right on but can we infer it from the information provided???
Secondly, it's mentioned that the discontinuation of the vaccination program has started just at the beginning of this year. So is it safe to assume that all young children up till the beginning of this year have been vaccinated?? So the threat is actually to infants, toddlers under the age of 1? Or are young children a broad category which includes the infants???
Would really appreciate your views on this... Thanks a tonne.

Dear RahulSingh13,
I'm happy to respond.

My friend, think about why the GMAT asks CR questions. The GMAT asks CR questions fundamentally because it wants to test your critical reasoning skills. People who have good critical reasoning skills will be successful in the business world: these are the people who can look at a set of disparate facts and deduce what is really happening and what needs to be done. The folks who have these insights are able to grab opportunities and prosper. The folks who are super-careful not to make any move until they know for sure will miss one opportunity after another. Think about your statement: "I believe we are not supposed to make assumptions on CR questions unless specifically asked to do so." With all due respect, this is the attitude of an obedient rule-follower. Obedient rule-followers are not the folks who are wildly successful in the business world, and business schools are not particularly interested in folks whose greatest asset is being obedient rule-followers. Your primary job on the GMAT CR is to use your intelligence to discern what is going on. The question absolutely demands that you use critical thinking skills to see beyond what is literally said to what is really happening.

There is a great deal of confusion about the issue of CR questions and outside knowledge. See this blog:
https://magoosh.com/gmat/2014/gmat-criti ... knowledge/
It's perfectly true that you need not be an expert in the specific topic that the CR prompt discusses. But, it's also true that you need to have a general idea of how the world works, and you have to recognize real world patterns that will come into play. The CR prompt might not state it specifically, but you need to recognize the law of supply and demand, or general facts about crime and trial law, or the nature of academic degrees, or what might motivate doctors or politicians or drivers or criminals or policemen or generals or home owners. In other words, you have to have an intelligent understanding of the world in which you live and the general patterns of why people make the choices they make. When you show up for your B-school interview, if they ask you some general things about the real world and you are naive in your understanding, you will not look good. An attractive B-school candidate is someone who can demonstrate that he is savvy about the push-and-pull of the real world.

In this question, it's perfectly true that you are not expected to be a medical expert about these specific diseases----these diseases are fictional anyway, so nobody in the world is an expert on them! It's also true that having a general knowledge of the difference between viruses and bacteria, as well as the general knowledge of how and why vaccines work, is simply something that every intelligent person should understand. If you don't know about this, you should consider it your responsibility to read up on it. These are not "assumptions"---these simply reflect an understanding of how the world works, and calling on this knowledge in this question an example of the kinds of critical thinking skills that the GMAT expects you to have!

As to your other question, infants are included as part of young children. Also, the nature of (A) is a prediction, in the future tense ---- in a year or two, the infants will be toddlers. We don't know when in the future the infection will be likely to occur, but the term "young children" includes both the infants now and the toddlers of a year or so away.

Does all this make sense?
Mike

Hi Mike,

Firstly, I apologize if the the tone of my query came across a bit too strong and critical, that wasn't my intention. I've just started on my gmat preparation and my question drew from the prep material I've been referring to. When i said "we are not supposed........unless asked to do so", I was quite simply alluding to the "make an assumption" question type.

As it so happens, even i chose option A on a line of reasoning very similar to yours.
The intention of asking this question was to genuinely try and understand what can be considered as "bringing in outside knowledge" into an argument. The link you've posted is very helpful in that regard and i thank you for that.

With all due respect, making assumptions about my intelligence, attitude and future prospects based on perhaps an ill-framed question, seems like a leap in itself.
If you knew the first thing about me, "obedient rule follower" was the last thing you would have said

Dear RahulSingh13,

I'm happy to respond. My friend, thank you very much for a thoughtful and sincere response. I apologize if I appear to have made any unwarranted assumptions about you. In my responses in this public form, I try to address both the specific individual and whoever else might read the response. I have heard many students on GC fall into a pattern of "just tell me what to do," and I always like to warn against the long-term pitfalls of this approach.

It's clear to me from your response, my friend, that you are an intelligent individual with a strong sense of character. I respect that, and I know that adcom and potential employers will respect it as well. I wish you abundant success in your future. Let me know if I can ever be of help in explaining other questions on this site.

Mike

Hello Mike

I am still not able to digest this logic - Given that we are being asked for a conclusion, we are assuming a lot of things here:
1. The virus is passive. We don't know as to whether the vaccine terminated the virus or rendered it passive only
2. Passive virus cannot become active (in one individual and spread in adults) and hence can only affect children. For e.g. if instead of children in option A, if we would have said older population (may be they lost immunity), will this option still be a correct one

In what I've learned so far for conclusion questions --> Whatever exists in the stem is truth in entirety and hence I am skeptical on the reasoning you have provided.

Would be happy to hear from you.

Thanks
Saahil

Dear rsaahil90,
I'm happy to help. I think, in part, the problem is that you don't understand the basics of vaccines and viruses.

Right now, in all likelihood, you and I and most of the people we know have the polio virus in our bodies. We got the virus sometime during our lives, but because we were fortunate to get the polio vaccine when we were young, our immune system is educated about how to fight the polio virus, so we never developed any of the symptoms of polio. You see, a vaccine does not terminate a virus: a vaccine does nothing directly to the virus itself. The job of a vaccine is to educate the human immune system, as it were to "teach" the immune system how to fight a disease, so that we don't have to go through having the disease. Every vaccine you and I have received has taught out how to fight those particular viruses (polio, mumps, measles, diphtheria, etc.) In all likelihood, we have encountered all these virus during our lives and may carry these viruses in our body. Because our immune systems know how to fight these diseases, we don't get these diseases, but the viruses are there, and theoretically, at any time we could infect an unvaccinated person, if we ever were to encounter one.
So far as I know, the immunity that one gets from vaccines does not diminish in old age---old folks have other immune problems, but I have never heard of an old person getting polio or mumps or measles or etc. after they had been vaccinated in youth.
The word "passive" in this context is not a medical term: I was simply trying to describe the situation of these viruses in our bodies: they are present but they don't make us sick. Once again, if the virus is present, then even though I am not sick, I could be carrying it and could infect someone else, if that other person had not been vaccinated.

Once again, all this is not specialized knowledge. The details of exactly how a vaccine works, exactly how vaccines are manufactured, the biochemistry of the immune system's response to them---all that is specialized biological knowledge. The overview I have given, by contrast, is something that every intelligent person should know. Every intelligent person should know that antibiotics kill bacteria but have zero effect on viruses. Similarly, everyone should know that a vaccine enhances the human immune system, enabling the immune system to fight a virus, but the vaccine itself does zero to the virus. No medicine and no drug can fight a virus: the most drugs can do is manage symptoms. If a virus is in, say a pot of water, we can destroy the virus by boiling the water. We can destroy virus outside the body by heat or chemical means, but a virus inside the body is considerably harder to fight. Basically, the only thing on Earth that we know that can fight and destroy a virus inside us is the human immune system itself, and vaccines brilliantly harness this power of the immune system to fight particular viruses. Once again, all this is in the realm that every intelligent person should know, and this "background knowledge" is crucial for understanding GMAT CR questions.

Does all this make sense?
Mike