3 ms·
> Doc Complete dropped from 3.63 seconds to 1.14 seconds (-214%). This is a pet peeve of mine. Percentage changes should be measured using the original value
by recursive 15y ago
> Doc Complete dropped from 3.63 seconds to 1.14 seconds (-214%).
This is a pet peeve of mine. Percentage changes should be measured using the original value as the denominator, not the new value.
- dredmorbius 15y agoThe pedant uses the delta over the mean of the old/new values. So: 100 * (1.14 )/((1.14 + 3.63)/2) or -104%
- Rexxar 15y agoMay be I'm missing something, but this way of computing a percentage seems completely meaningless to me.
- dredmorbius 15y agoIt's unbiased toward either the beginning or ending value. If you want to overstate a change, you'll use the smaller value as the denominator. If you want to understate a change, you'll use the larger. If you use the mean of the two, you're giving a value that's not biased by either of the two extremes. There are arguments for using other methods. As usual, Wikipedia has a good discussion of alternatives: http://en.wikipedia.org/wiki/Relative_change_and_difference http://en.wikipedia.org/wiki/Relative_change_and_difference
- recursive 15y agoWhen talking about a starting value and a new value, I find the percentage change formula on the page you referenced to be the most logical. When considering a change, your frame of reference is usually the original value. http://en.wikipedia.org/wiki/Relative_change_and_difference#Percentage_change http://en.wikipedia.org/wiki/Relative_change_and_difference#...
- wladimir 15y agoAgreed. -214%, the way I interpret it intuitively, would mean the new value flips sign. -XXX% where XXX is bigger than 100 therefore looks strange.