ETS doesn't take off 1 /4 of a point for each wrong answer in order to punish you for guessing. They do it so as not to reward you for blind guessing. Suppose, without even glancing at any of the questions, you just randomly entered responses in the first 20 spaces on your answer sheet. Because there's a one-in-five chance of guessing correctly on any given question, odds are you would guess right for 4 questions and wrong for 16 questions. Your raw score for those 20 questions would then be:
Because of the 1/ 4 point penalty for wrong answers, you would be no better off and no worse off than if you'd left those twenty spaces blank.
Now suppose in each of the first 20 questions you are able to eliminate just 1 possible answer choice so that you guess with a 1/4 chance of being right. Odds are, you'd get 5 questions right and 15 questions wrong, giving you a raw score of:
All of a sudden, you're more than a point up. It's not much, but every little bit helps.
The lesson to be learned here is that blind guessing doesn't help, but educated guessing does. If you can eliminate even one of the five possible answer choices, you must guess. We'll discuss how to eliminate answer choices on certain special kinds of questions later in this chapter.
Guessing as Partial Credit
Some students feel that guessing is similar to cheating—that guessing correctly means getting credit where none is due. But instead of looking at guessing as an attempt to gain undeserved points, you should see it as a form of partial credit. For example, suppose you're stumped on the question mentioned earlier—which asks about sodium ions and transport channels in an animal's cell membrane—because you can't remember if the sodium should flow into the cell or out of the cell. But let's say you do know that phagocytosis occurs when a cell engulfs a particle that is much larger than an ion. And suppose you are pretty sure that the answer isn't simple diffusion, because sodium ions do not cross cell membranes without help. Don't you deserve something for that extra knowledge? Well, you do get something: when you look at this question, you can throw out A, B, and E as answer choices, leaving you with a one-in-two chance of getting the question right if you guess. Your extra knowledge gives you better odds of getting this question right, exactly as extra knowledge should.
