I play video games; I need to know if the percentage is additive or multiplicative.

"+100%" looks pretty good until you see what "×25%" actually gives you.

Dark Souls cleared this up for me real quick.

So you're telling me there's a chance?

In game design, it has to be stated whether it’s multiplicative or additive. Sometimes a logarithmic function is used as well, with increases in efficiency as 1 / ( 1 + bonus ). This allows you to always add more bonus, but there’s diminishing returns.

I work in a place full of statisticians, and we've had to unfortunately have numerous conversations with some of them about the difference between "a decrease" and "a decrease in the rate." Apparently "it's increasing slower" isn't clear enough for some.

When my son was about to be born my mother in law caught wind that we didn't plan on circumcising (before researching it I mostly felt it was just strange to do cosmetic surgery on a newborn) but her argument was mostly parroting the 50% reduction in this that and the other disease, missing the fact that it was going from a 0.5% chance to a 0.25% chance, but of course introduced new risks by nature of being a surgery.

Naturally after looking more into it I learned just how bonkers circumcision is so I was far more cemented in my position

That's why when presenting numbers at work, we always distinguish a movement of X % (percent) from a movement of X ppts (percentage points)

Convert percentage to fraction, i.e, 80% become 0.8 Then multiply with initial value

If it says 80% more use initial + (initial*80) or simply initial*1.8

Or if it says 80% less, use - in above calculation or multiply by 0.2

I find percentages more neat when used as fractional number Edited to escape the multiplication symbol

People got this wrong about inflation as well. In 2020 there was actual deflation, and in 2021 there was very minimal inflation, meaning prices were still largely lower or similar as 2019. Then we saw 9% inflation in 2022. Total inflation in 2024 vs the 2019 benchmark was around 15%. Or 3% average per year, which is barely over the baseline. People just hear 9% inflation, completely missing the fact that this was a YoY number relative to the Trump recession.

Difference between increase of x% (old percentage + old percentage * x%)% and increase of x percentage points (old percentage and x)%