It's the same as accounting. If people are allowed discretion to use their judgment to pick the most accurate reporting methods for each time and situation, or

It's the same as accounting. If people are allowed discretion to use their judgment to pick the most accurate reporting methods for each time and situation, or the statistics that best reflect reality, then inevitably you end up with nothing but lies. If you standardize reporting, then sometimes you end up reporting meaningless numbers, but everyone is in the same boat, and there's less long-term distortion (as long as the people who wrote the standard have an interest in accurate information.)