This recent question:

50% UP, 50% DOWN, is still 25% down. How do you make percentages work for you? (old title)
Help me understand the oddity of percentage gains and losses?

is apparently based on a misunderstanding of how percentage returns work. All three answers attempt to correct the questioner's understanding. However, I don't see this type of question as being particularly valuable or useful to this site. If anything, reading such a question may only confuse unsophisticated readers and may deter more sophisticated users from participating in a site where such questions are taken seriously.

Has this site developed an official policy towards questions based on faulty assumptions or logic?

Note that Robert Cartaino believes one of this site's biggest problems is an over-abundance of low quality questions.

  • What exactly is the false premise, BTW? Can you spell it out for us. Commented Jan 1, 2012 at 17:33
  • 1
    The false premise is that something other than basic algebra underlies the phenomenon in question. Commented Jan 1, 2012 at 21:21
  • I don't see such an implication. How do you come to that? Commented Jan 2, 2012 at 0:52
  • 2
    The OP seems to think that algebra works to his "disadvantage". Commented Jan 2, 2012 at 4:00
  • See my expanded answer below. I invite you to state your own position in an answer as well, if there's a different course you think we should be taking. Commented Jan 2, 2012 at 15:15

3 Answers 3


I think that this particular question is not based on false premises (which is OK, that's why people ask questions - because they don't know something or know something wrong), but on false understanding of basic math.

I'm not sure answering the question in any way other than the first 3 answers (which explained to the OP what percents are and how to use them) would help, because the OP lacks the basic math background to understand it.

I don't think that teaching math is the goal of this site either, so I voted to close.


I answered that question. I hesitated, as something didn't feel quite right about it, but figured as Chris states, it's for the group to close/delete.

  • "The group" is you, me, and other high-rep users of this site. If you believe a question isn't quite right, why wouldn't you vote to close? I'm trying to make the case that leaving these open actively detracts from the site and encourages low-quality questions. What is your opinion on that specific point? Commented Jan 3, 2012 at 21:44
  • I felt the question was in the gray area. In general, I vote to close when to me, it's clear that's the right move. Often, a closed question will get one or two answers before others decide to close it. I saw this one as a math question that had a legitimate answer. Commented Jan 4, 2012 at 5:52

For poor quality questions (in general), the community can vote-to-close as (say) "not a real question", and then vote to delete the question. This happens often. In effect, poor quality questions eventually get removed from the site.

However, I'm not sure we want to remove questions "based on a false premise" as a matter of policy.

Questions – by design – are frequently asked by people who aren't as enlightened as potential answerers about the subject matter under discussion. An OP can make a mistaken assumption or an unreasonable leap of logic. I don't think that's necessarily fatal for a question.

Such faults in the question can be addressed in the answer. Other times, comments can help shape/fix the question so the phrasing makes more sense. In other cases, the question may not be salvageable at all.

I think many people make mistakes when thinking of investment gains and losses in percentage terms only, and for that reason I see value in this kind of question-with-a-false-premise. Perhaps a better title for the question might be "Help me understand the oddity of percentage gains and losses" instead of "... How do you make percentages work for you"?

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