Why do people call a decrease of 40% to 20% a decrease of 20% instead of 50%?

[Dennis S]

?

[OWC Jamie]

What people ?

:quotes: journalists :quotes: ??

[rjmacs]

Because they can't trust their audience to know basic math.

Also, it's just another way of saying the same thing. One expresses a relative change, the other an absolute change.

Somebody put 50% more pee in someone's Wheaties this morning?

[M A V I C]

It depends on if you're in marketing or not.

Marketing would say at least a 50% decrease, if not 500% or 5000%.

[WHiiP]

I'd say "for a fact" the "journalists" don't have a CLUE.

[Lux Interior]

rjmacs wrote:
One expresses a relative change, the other an absolute change.

Yes.

Reference point.

Also confusing is increasing by 50%, then decreasing by 50%, but not ending up in the same spot.

[cbelt3]

90% of the population is bad at math. The other 15% aren't that much better.

[rz]

I argued a similar point at a sporting goods store once. Their clearance prices were 50% off. They came over the loudspeaker and said that for the next half hour, all clearance items were 75% off. So I bought something. When the clerk rang it up, she took 50% off. Then she took 25% off of that total. I explained three times that she was wrong.

If you take 75% off of $100, it's $25
If you take 50% off of $100, it's $50. If you then take 25% off of that, it's $37.50

She finally had to get a manager to ring it up properly.

[JoeH]

Actually, without the rest of the information about what is being done, that would be the correct way to describe this decrease. Is it a 40% tax rate being decreased to 20%? The the rate was decreased by the value of 20%. You could also say the rate was cut in half.

[N-OS X-tasy!]

Lux Interior wrote:
[quote=rjmacs]
One expresses a relative change, the other an absolute change.

Yes.

Reference point.
Percentages are relative by nature. Understanding that is crucial to successfully communicating when discussing percentages. Unfortunately, most people do not understand that, partially because most people barely grasp the concept of percentage to begin with.