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That article (i.e. the author) seems to have a weird understanding of mathematics: > "Note that there are two ways to calculate increases. We can measure an in

That article (i.e. the author) seems to have a weird understanding of mathematics: > "Note that there are two ways to calculate increases. We can measure an increase in absolute terms, e.g., a rise from 5% to 15% of teens with a diagnosis is a ten percentage-point increase, or we can report it in relative terms, e.g., a rise from 5% to 15% is a 300% increase, relative to the anchor point" Uhm… maybe in an "alternative mathematics" universe? Where I learned math, an increase from 100% of the anchor value to 300% of the anchor value is not a relative increase of 300% but of 300%-100%=200%. In contrast, A "300% increase, relative to the anchor point" would be adding 300% of the anchor value to the 100% of it that it already has, i.e. resulting in an end value of 400% of the anchor value. So in the case presented by the article quote, to come back to the absolute terms, it would be a rise from 5% to 20%, not to 15%.

sbirch 4y ago
I think you've mixed up relative and absolute differences. Both of your examples are in terms of absolute percentage points (pp, sometimes ambiguously labeled %), but relative changes are measured in percent (%). 300% relative difference just means 300/100 = 3x.
- EntrePrescott 4y ago
  > Both of your examples are in terms of absolute percentage points No, they are both about relative increases. I didn't even write about absolute increases because (unlike relative increases, where the article makes a mistake) absolute increases were the part that the article got right: a rise from 5% to 15% would be an (absolute) increase of 10% … just like the article says. > 300% relative difference just means 300/100 = 3x …My point was: 300% relative INCREASE (i.e. positive relative difference) means that it's the DIFFERENCE (increase) between the initial value and the end value that is 300% RELATIVE TO the initial value (thus the end value being 400% of the initial value), not that the end value is 300% of the initial value (which would only be a 200% relative increase). Let's take, to better illustrate the point, an example with a relative increase below 100%. Let's go with an example with 40% relative increase. So let's say: * in the reference year, your company made a profit of 5 million dollars out of a revenue of 100 million dollars, i.e. a profit margin of 5%. * the next year it still made a revenue of 100 million dollars but managed to be more profitable, making a profit of 7 million dollars i.e. a profit margin of 7%. * The ABSOLUTE increase of the profit margin is (7%-5%)=2%, * The RELATIVE increase of profit margin is the absolute increase of profit margin divided by its initial reference value i.e. (7%-5%)/5% = 40%. And my point is: having a 40% relative increase of profit margin means that your end profit margin is 40% higher relative to your initial reference profit margin and is thus (100%+40%)=140% of your initial reference profit margin, not that your end profit margin is 40% of your initial profit margin… which would be a 60% relative DECREASE (i.e. -60% relative increase) of the profit margin.

sbirch 4y ago

I think you've mixed up relative and absolute differences. Both of your examples are in terms of absolute percentage points (pp, sometimes ambiguously labeled %), but relative changes are measured in percent (%). 300% relative difference just means 300/100 = 3x.

EntrePrescott 4y ago
> Both of your examples are in terms of absolute percentage points No, they are both about relative increases. I didn't even write about absolute increases because (unlike relative increases, where the article makes a mistake) absolute increases were the part that the article got right: a rise from 5% to 15% would be an (absolute) increase of 10% … just like the article says. > 300% relative difference just means 300/100 = 3x …My point was: 300% relative INCREASE (i.e. positive relative difference) means that it's the DIFFERENCE (increase) between the initial value and the end value that is 300% RELATIVE TO the initial value (thus the end value being 400% of the initial value), not that the end value is 300% of the initial value (which would only be a 200% relative increase). Let's take, to better illustrate the point, an example with a relative increase below 100%. Let's go with an example with 40% relative increase. So let's say: * in the reference year, your company made a profit of 5 million dollars out of a revenue of 100 million dollars, i.e. a profit margin of 5%. * the next year it still made a revenue of 100 million dollars but managed to be more profitable, making a profit of 7 million dollars i.e. a profit margin of 7%. * The ABSOLUTE increase of the profit margin is (7%-5%)=2%, * The RELATIVE increase of profit margin is the absolute increase of profit margin divided by its initial reference value i.e. (7%-5%)/5% = 40%. And my point is: having a 40% relative increase of profit margin means that your end profit margin is 40% higher relative to your initial reference profit margin and is thus (100%+40%)=140% of your initial reference profit margin, not that your end profit margin is 40% of your initial profit margin… which would be a 60% relative DECREASE (i.e. -60% relative increase) of the profit margin.