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Absolute change is the actual change in units. It could be the actual change in pounds, degrees, inches, percentage points, or lots of different things.
EXAMPLE
Suppose a political candidate's approval rating went up from 44% to 48%. That absolute change is four percentage points.Relative change is the percent difference from the previous value, and it's always expressed as a percent.
IN CONTEXT
An infant weighed 6.5 pounds at birth, and 1 year later, weighed 14.5 pounds. Decide if each of the following statements is true.
Statement 1: The infant's weight change was an increase of 8 pounds.
Well, that's a true statement; 14.5 minus 6.5 is 8 pounds. It increased by 8 pounds.
Statement 2: The infant's weight change was an increase of 123%.
This one's a little bit less obvious, but it's also true. The 8-pound increase was more than double what the birth weight was. It was an increase of over 100%. In fact, when you do the calculation, 8 divided by 6.5 is 123%.
How do you calculate absolute change? Another word for it is the absolute difference. You simply calculate the difference between the new and the old.
In the example above, 14.5 minus 6.5 was a difference of 8 pounds.
The relative change, or the relative difference, is calculated by taking the absolute difference and dividing it by its originating value.
In the example above, the absolute difference was 8 pounds, and the original value was 6.5. When you put this into a calculator, you get 1.23.
Consider the following example that shows this year's and last year's enrollment at Memorial High School.
IN CONTEXT
Let's look at another example. The following table shows the results of the 1990 census and the 2000 census, along with the absolute change and relative change.
State 1990
Population2000
PopulationAbsolute
ChangeRelative
ChangeFlorida 12,937,926 15,982,378 3,044,452 24% Georgia 6,478,216 8,186,453 1,708,237 26% Hawaii 1,108,229 1,211,537 103,308 9% Idaho 1,006,749 1,293,953 287,204 29% Illinois 11,430,602 12,419,293 988,691 9% Indiana 5,544,159 6,080,485 536,326 10% Iowa 2,776,755 2,926,324 149,569 5% Kansas 2,477,574 2,688,418 210,844 9%
Absolute Change: To calculate the absolute value, simply subtract the 1990 value from the 2000 value. For example, Florida's absolute value can be found by subtracting 12,937,926 from 15,982,378 to get an absolute change of 3,044,452.
All of the states in the list had increases in the population. Some were not very much, like Hawaii, which only had about a 100,000-person increase. Some were a lot, like Georgia and Florida, whose population increased by over a million people. The highest absolute change was 3,044,452 people, in Florida.
Relative Change: The question of which state had the largest relative change between that time is a little bit different. Looking at Florida again, you need to figure out if the absolute change of around 3 million was a large change percentagewise from the old population of about 13 million. It was a large increase, but was it the largest percent increase in the list?
To find the relative change, take each absolute change and divide by the old population from 1990.
Florida's relative change was positive 24%—approximately 3 million divided by 13 million gives you about 24%. Georgia's increase was about 26%, a little bit larger of a percent increase than Florida. The highest of the list was a 29% increase in the state of Idaho. Notice it didn't have a very large absolute change. But its population wasn't very big to begin with, so even a small absolute change can be a large relative change.
Source: THIS TUTORIAL WAS AUTHORED BY JONATHAN OSTERS FOR SOPHIA LEARNING. PLEASE SEE OUR TERMS OF USE.
