Symbols for "YES" and "NO" in formal English writing

X for No and O for Yes are clearly understood by everyone in Japan, but not in English. In fact, in my first Japanese class in the US, when the teacher used these symbols, I thought that X meant Yes because "X marks the spot."

In my own Japanese to English translation, for tables, I usually spell out "Yes" and "No." For the circle, triangle, and X (i.e., three-level symbols), you can use, for example, A, B, C or Excellent, Good, Poor, or any other easy shorthand.

If you do use the Japanese-style symbols, you should use a key at the table to explain the symbols because they are not readily understood by English speakers.

Using a checkmark in a table is fine for Yes. In that case, however, there is no need for an X for No because the absence of the checkmark implies No. You can also use a solid dot symbol for Yes (opposite of the Japanese meaning), and again the absence of the dot would imply No.

I am a native English speaker, with what I hope is an above average education. I can think of no good reason, especially for a conference paper, to use anything other than "Yes" and "No" when what you mean is "Yes" or "No".

I'd also consider using Y for Yes and N for No. I think this is clear for everyone speaking English. It may look worse in the manner of design but will be understood by all.

✓ and ✗ (or V and X if you stick to ASCII) seem to be understood correctly when all cases are filled. Reinforcing with colors (green and red respectively) helps to avoid confusion as well, when using colors is an option (example).

Also check out the "No" symbol (ironically, it is somewhat close to Japanese "Yes" symbol). Using ✓ and ⃠ symbols avoids the confusion with ✗ being interpreted as "marking the spot", meaning "yes".

IMO the most unambiguous symbol for "sometimes yes, sometimes no" would be a ?. If you go for + and -, then using ± as "sometimes yes, sometimes no" is an option as well. I have never seen a △ used in that sense in English, so I'd avoid it at all costs.