06 July 2014

Hard questions, easy answers (or: when you hear hoofbeats, think horses, not zebras)

Perhaps you’ve heard the saying “when you hear hoofbeats, think horses, not zebras.” If you’re not familiar with the expression, it means that when searching for an explanation, you should always consider obvious possibilities before thinking about more unlikely options. Whenever I tutor the Writing section of the SAT, I find myself uttering these words with inordinate frequency.

I’ve worked with a number of students trying to pull their Writing scores from the mid-600s to the 750+ range. Most have done well on practice tests but then unexpectedly seen their scores drop on the actual test. Unsurprisingly, they were puzzled by their performance on the real thing; they just couldn’t figure out what they had done differently. And at first glance, they did seem to know what they were doing. When I worked very carefully through a section with them, however, some cracks inevitably emerged. Not a lot, mind you, but just enough to consistently pull them down. They would be sailing along, identifying errors like there was no tomorrow, when all of the sudden they would hit a question whose error (if any) they simply could not identify.

When that happened, they would stop and read the sentence again. And when they couldn’t hear anything wrong, they would read the sentence again, slowly, trying to hear whether something was wrong (mistake #1). Then, if they really didn’t want to choose “No error” but weren’t sure whether something was truly wrong, they would start searching for an explanation, usually a somewhat convoluted one, for why a perfectly acceptable construction was ambiguous or awkward or otherwise wrong (mistake #2). Almost always they did so when the actual answers — answers based on concepts they understood perfectly well — were staring them right in the face.

One of things that it’s easy to forget — or, in the case of many natural high-scorers who haven’t needed to study the framework of the test, to never realize — is that “hard” questions are not necessarily hard because they test hard concepts. Most often, they are hard either because they test (relatively) simple concepts in hard ways or because they combine concepts in unexpected ways.

Hard questions can — and often do — have “easy” answers. That does not mean that the answer is the option that sounds weird (that’s the distractor answer). It does, however, mean that the answer is likely to be an extremely simple word like “is” or “are” or “it.” It also means that the answer probably involves an extremely common error, like subject verb agreement or pronoun agreement, not some obscure rule you’ve never heard of.

The challenge is figuring out which concept is being tested, not understanding the concept itself. So when people who can usually hear the error come across a question whose answer they don’t instantly hear, their instinctive reaction is to look for something outlandish to be wrong with it, not to think systematically about what the most common errors are and check to see whether the question contains them. In others words, they hear hoofbeats and imagine that a herd of zebras is about to come racing around the corner.

For example, consider the following question, which a very high-scoring student of mine recently missed:


(A) Thanks to the strength (B) of the bonds between (C) its

constituent carbon atoms, a diamond has exceptional

physical properties (D) that makes it useful in a wide

variety of industrial applications. (E) No error


If you spotted the error immediately, great, but bear with me for illustrative purposes. The sentence itself is rather challenging: it discusses a topic (chemistry) that many students are unlikely to have unpleasant associations with, and it also contains the word “constituent,” which many weaker readers will have difficulty decoding, and whose meaning many slightly stronger readers will not know or be able to figure out. So right there we have two big stumbling blocks likely to distract from the grammar of the sentence. Many test-takers are also likely to think that “Thanks to” sounds too casual and would be considered wrong on a serious test like the SAT. Many other test-takers are likely to just not hear any error.

In that case, the most effective approach is to consider the structure of the test. The most common error is subject-verb agreement, and when in doubt, it’s the error you should always check first. There is exactly one underlined verb in the sentence: “makes.” It singular (remember: singular verbs ends in “-s”), which means that it’s subject must be singular as well.

But what is the subject? “Physical properties,” which is plural, so there’s a disagreement. The answer is therefore (D). The sentence should read “…physical properties that make it useful.”

The moral of the story is that if you don’t spot an error immediately, whatever you do, don’t fall into the loop of endlessly rereading the sentence and trying to figure out whether something sounds funny. Instead, check systematically for the top five or so errors: subject-verb agreement, pronoun agreement (check “it” and “they”), verb tense (pay attention to dates and “time” words), adjectives vs. adverbs (easy to overlook), and, if you’re at the end of a section, faulty comparisons.

If all of those things check out, the sentence is probably fine.

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