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Indeed. When I'm doing a technical interview, and I ask a question, I want the person I'm asking to tell me if they don't know the answer. If they tell me that they don't know the answer, I'm more confident that when they are stuck on a problem in the real world, they will come and ask someone, or look it up, rather than just trying to bullshit their way through. In the real world, guessing can be considerably more dangerous than admitting that you don't know something and thus taking the effort to actually find it out.

Test motivation differs from person to person, so if you don't encourage everyone to at least try every question and guess, you'll get differences in scores which don't reflect the child's difference in knowledge (which is what the test is trying to measure) so much as willingness to try or guess. This willingness can differ systematically so you might get drastically lower scores for poorer children than they should. (This is one of the reasons schools like psychologists to do IQ tests, because they can spot when a child isn't trying or is deliberately underperforming.) So that's one reason. Another reason is that it's rare to have no idea whatsoever; even if you feel entirely uncertain, you can still often guess at above chance rates, showing that you did know more than nothing. Forced-choice methodologies expose that knowledge and again make the tests more accurate, because more items means more effective at distinguishing between students.

(Imagine a test of 10 questions, each substantially harder; one student manages to answer correctly up to question 5 before starting to feel uncertain and refusing to answer any more, and a second gets up to question 6. How sure are you that #1 knows less than #2? Now imagine that they instead 'guessed' on the remaining 5 questions, and #1 got 3/5 right and #2 got 1/4. Now how sure are you? Haven't you learned something from this apparently 'useless' guessing?)

> But in the real world, there is no 25% credit for guessing.

You can no more refuse to guess in the real world than you can refuse to make choices, take actions, or let time pass.

I'm not saying there aren't any valid reasons for doing it. I'm just saying the there's a "meta-lesson" there that has to be corrected. I want all my kids to grow up knowing that there's no shame in saying "I don't know," if you honestly don't know. Life is not a sounding smart contest.

>> Why they do this, I have no idea.

> I'm not saying there aren't any valid reasons for doing it.

> I'm just saying the there's a "meta-lesson" there that has to be corrected.

And I'm saying that your meta-lesson is not a good idea as it will tend to teach underconfidence. The real world does not always let you off with a "I don't know"; you may not know to some high degree of certainty whether a cancer treatment is a good idea, but nevertheless you must decide whether or not to do it.

You may want to teach your brother how to guess, because a solid educated guess is also an opportunity for you to assess his level of understanding.

A student guess is an opportunity for you to learn what they understand and what they still need help with. If a student makes an attempt on a well-written multiple choice test, the attempt can show the teacher exactly what the student does and doesn't understand.

The right approach to guessing can communicate a lot, and partial credit may be justified if, for example, the student correctly factors a quadratic equation but fails to remember how to compute the intercepts from the result. That would tell a teacher that the student remembers part of the lesson but needs help with the rest.

I think because on a test they can't win or benefit from leaving an answer blank, but they can "win" a bit by guessing.

Now if say they are penalized for guessing -- they they pick A and then later asked to explain but they fail and get points taken off for example. Then guessing might be discouraged.

Another reason could be that maybe teachers believe that a student somehow knows the answer subconsciously and just guessing will tease that out. Or not trying to guess, means they have given up and are not engaged. Like say they don't answer, and leave a space blank, maybe to a grader it looks like "this person is lazy and don't want to work".

Anyway, you can interpret that in many ways.

When teaching though, I agree, that should be discouraged, but in a crucial end of the year standardized test it makes sense. And I guess our whole education system has shifted to "teaching to the test" then it makes to just practice tests all the time and not even bother "teaching" for knowledge's sake.

I've never heard of a guessing reward before. I've heard of guessing penalties, though. Back when I took the AP exams, there was a penalty (negative points awarded) for guessing, whereas leaving a multiple-choice question blank was worth 0 points. (This stopped being the case in 2011.)

Are you sure it's a guessing bonus? I teach the LSAT. On that test, there's no guessing penalty, and you get a point for a correct answer.

So, if you guess five questions, on average you'll get a point, making each guess statistically worth about .2

But guesses don't have actual value of course, it's only when you guess right that you get the points.

I can't speak for the grade school standardized tests since I don't teach those (nor do I want to).

You could be right. I'm not sure.