[soreal]

The authors calls out: [Important note: here we are not using the term “confidence” in the technical sense used in statistics, but rather as an informal term for “subjective probability”.]

But then goes on to use a very technical, statistical version of confidence where 0% confidence is somehow equal to 100% confidence you picked the wrong answer.

All of this leads me to assert that despite the math being internally consistent, it does not apply well to the situation. A rational outside observer without reading such an article would assume that 0% confidence in your answer is equal to a 50% chance of being right.

The phrase "confidence that the answer is 'true'" can easily be interpreted as "confidence that the answer I marked is correct".

[hfanson1]

It is confidence that the answer is true. 100% being fully sure the answer is true. 0% being fully sure the answer is false. 50% should be used for both true and false have the same probability.