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 = 114, v2 = 115.8.
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: - 74.
- Choose a random positive number for the end value: 3.
Formula and calculation:
(v1 - v2) / v1 =
(- 74 - 3) / - 74 =
-77 / - 74 ≈
1.040540540541 ≈
1.04
Although the absolute difference is negative: -77, the relative decrease change is positive: 1.04. 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:
(114 - 115.8)/|114| =
- 1.8/114 =
- 1.8 ÷ 114 =
- 1.8 ÷ 114 × 100/100 =
(- 1.8 × 100 ÷ 114)/100 =
(- 180 ÷ 114)/100 =
- 1.578947368421/100 =
- 1.578947368421% ≈
- 1.58%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 114 to the final, end value 115.8:
Not rounded = - 1.578947368421%
Rounded off to max. 2 decimal places ≈ - 1.58%
The absolute (actual) difference
114 - 115.8 = - 1.8
By what percentage has 114 decreased?
Answer: By ≈ - 1.58%
By what percentage is 115.8 smaller than 114?
Answer: By ≈ - 1.58%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).