The relative decrease change. Definition:
The relative decrease change is the difference in an indicator over two periods in time, v1 - v2, relative to the value of the indicator in the earlier period, v1.
- Where:
- v1 - is called the reference value (original, initial number);
- v2 - is called the new value (the end value).
- In our case: v1 = 123, v2 = 163.3.
The relative decrease change. Formula:
The relative decrease change =
The actual change / |v1|
(v1 - v2) / |v1| =
- Legend:
- v1 - the original number
- |v1| - the positive value of v1, |v1| >= 0. By example: |10| = 10; |-10| = 10.
- v2 - the new value
- The actual change = v1 - v2
- / - the fraction bar (division)
Why do we use |v1| in the formula instead of v1?
- Let's see what happens if we use v1 instead of |v1|:
- Choose a random negative number as the initial value: - 88.
- Choose a random positive number for the end value: 81.
Formula and calculation:
(v1 - v2) / v1 =
(- 88 - 81) / - 88 =
-169 / - 88 ≈
1.920454545455 ≈
1.92
Although the absolute difference is negative: -169, the relative decrease change is positive: 1.92. By using |v1| instead of v1, the error is corrected.
The relative percent decrease change. Detailed calculations below
By multiplying a number by the fraction 100/100,
we change only the form of the result, not the result.
- 100/100 = 100% = 100 ÷ 100 = 1.
- n × 100/100 = (n × 100)/100 = (n × 100)%, any number.
The relative percent decrease change. Formula:
The relative percent decrease change =
The relative decrease change × 100/100 =
(The relative decrease change × 100)/100 =
(The relative decrease change × 100)%
Calculate the relative percent decrease change:
(123 - 163.3)/|123| =
- 40.3/123 =
- 40.3 ÷ 123 =
- 40.3 ÷ 123 × 100/100 =
(- 40.3 × 100 ÷ 123)/100 =
(- 4,030 ÷ 123)/100 ≈
- 32.764227642276/100 =
- 32.764227642276% ≈
- 32.76%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 123 to the final, end value 163.3:
Rounded off to max. 12 decimal places ≈ - 32.764227642276%
Rounded off to max. 2 decimal places ≈ - 32.76%
The absolute (actual) difference
123 - 163.3 = - 40.3
By what percentage has 123 decreased?
Answer: By ≈ - 32.76%
By what percentage is 163.3 smaller than 123?
Answer: By ≈ - 32.76%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).