


To Guess or Not to Guess?
Should you guess on the SAT? The answer lies deep within
this fake SAT question:

This question describes what happens when you
guess blindly on any SAT question. If you have five possible answer
choices and choose one at random, you have a 20percent chance
of choosing the right one. In other words, if you were to randomly
pick an answer on five of these multiplechoice questions
without even looking at the answer choices, you’d probably get one question
right for every five guesses you made.
Now think back to the .25 of a point taken
from your raw score for each wrong answer. This “penalty” isn’t
some random number. It’s strategically designed to eliminate any
gain you might get from guessing randomly. If you guess randomly
on five questions, getting one right and four wrong (as probability
states you will), your raw points for those five questions will
work out to
 1 right answer = 1 raw point
 4 wrong answers (–.25 points per wrong answer) = –1 raw point
This adds up to a grand total of 0 raw points.
So guessing’s a waste of time, right? WRONG. Read on.
The Grand Rule of Guessing
Guessing’s a waste of time if you’re guessing among five
answer choices. But there’s no rule saying you have to guess among
five answer choices. If you know how to guess wisely, how to eliminate
answer choices before guessing, the game changes. Take the following
Sentence Completion question:

We used this example because we thought you may not know
the meanings of the words anthropomorphic, sanguinary, sesquipedalian,
or sententious. All four of these words are more
obscure than the vocabulary that usually appears on the SAT. But
you probably do know the meaning of delicious and
can tell immediately that it does not fit correctly into the sentence
(a delicious dog?).
True, you still don’t know the right answer. All you’ve
done is eliminate one answer choice. But once you’ve eliminated delicious as
a possible answer, you only have to guess between four rather than
five choices. If you guess among these four choices, you’ll get
one question right for every three you get wrong.
 1 right answer = 1 raw point
 3 wrong answers (–.25 points per wrong answer) = –.75 raw points
This adds up to a grand total of .25 raw points. In other
words, if you can eliminate just one answer as
definitely wrong, the odds of guessing shift to your favor. And every
point or fraction of a point you can jam into your raw score is
worthwhile.
All this explanation adds up to The Grand Rule of Guessing:
If you can eliminate even one answer choice
on a question, always guess.
Guessing Wisely Is Partial Credit
Some students out there have a thing against guessing.
They have this feeling that guessing is cheating. They think guessing
rewards people who don’t know the answer and are just playing games
with the SAT.
If you’re one of those students, get over it. First, by
not guessing you’re hurting your own test scores. Second, guessing
intelligently is just a form of partial credit. We’ll use the example
of the Sentence Completion question about the dog guarding Hades
to make this point.
Most people taking the test will only know the word delicious and
will only be able to throw out that word as a possible answer, leaving
them with a one in four chance of guessing correctly. But let’s
say that you knew that sententious means “given
to pompous moralizing” and that no hound spouting pompous moral
axioms would be guarding the gateway to the Greek underworld. Now,
when you look at this question, you can throw out both delicious and sententious as
answer choices, leaving you with a one in three chance of getting
the question right if you guess.
Your extra knowledge gives you better odds of getting
this question right, just as extra knowledge should.
GridIns and Guessing
There’s no penalty on gridin Math questions. If you guess
and get one wrong, you won’t lose any points. But, and this is a
big “but,” the odds of randomly guessing the right answer on a gridin
is around ^{1}/
_{14400} . Even without
the guessing penalty, these low odds mean that if you have no idea
what the answer to a gridin question is, there’s not much value
in taking a wild guess.
If you have worked out a gridin problem, and have an
answer, grid it in. Even if you’re unsure of the answer, gridding
it in can’t hurt.
