1 year, 7 months ago
How do you calculate a percentage change from a negative figure to positive one?
For example,
2008: -150
2009: 200
The problem is, the way most people count it, you'd get a smaller percentage change if you increased '-150' to '-200' for example.
2008: -150
2009: 200
The problem is, the way most people count it, you'd get a smaller percentage change if you increased '-150' to '-200' for example.
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M$1 Answer
"you'd get a smaller percentage change if you increased '-150' to '-200"
that is actually a decrease because -200 is smaller than -150
What I think it is is the second number minus the first number divided by the absolute value of the first number (so it becomes from negative to positive)
The Wikipedia http://en.wikipedia.org/wiki/Percentage_change
article suggests that
So for
2008: -150
2009: 200
it's (200-(-150))/150=350/150=7/3 around 233 % increase
for the second case
(-200-(-150))/150=-50/150 around -33 % decrease
that is actually a decrease because -200 is smaller than -150
What I think it is is the second number minus the first number divided by the absolute value of the first number (so it becomes from negative to positive)
The Wikipedia http://en.wikipedia.org/wiki/Percentage_change
article suggests that
So for
2008: -150
2009: 200
it's (200-(-150))/150=350/150=7/3 around 233 % increase
for the second case
(-200-(-150))/150=-50/150 around -33 % decrease
You can leave an optional "tip" with Mahalo's virtual currency, Mahalo Dollars. If you are asking a difficult question that might require some research, or if you'd like a wide variety of feedback, a higher tip often leads to more answers to your question.
M$
"Which is wrong since the percentage of increase should be higher (400 increase compared to 350 for the first scenario) "
Why do you say it's wrong? The change is bigger in the second scenario indeed, but the *percentage* increase is smaller. That's why is called percentage because you divide by a value.
For example the change from 100 to 120 is higher than from 10 to 20, but the percentage change from 10 to 20 is higher than from 100 to 120
Sorry, I meant changing 2008 to -200 instead of -150. Using the first equation:
(200-(-200))/200=400/200=200%
Which is wrong since the percentage of increase should be higher (400 increase compared to 350 for the first scenario)