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 = 33.3, v2 = 41.3.
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: - 23.
- Choose a random positive number for the end value: 27.
Formula and calculation:
(v1 - v2) / v1 =
(- 23 - 27) / - 23 =
-50 / - 23 ≈
2.173913043478 ≈
2.17
Although the absolute difference is negative: -50, the relative decrease change is positive: 2.17. 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:
(33.3 - 41.3)/|33.3| =
- 8/33.3 =
- 8 ÷ 33.3 =
- 8 ÷ 33.3 × 100/100 =
(- 8 × 100 ÷ 33.3)/100 =
(- 800 ÷ 33.3)/100 =
- 24.024024024024/100 =
- 24.024024024024% ≈
- 24.02%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 33.3 to the final, end value 41.3:
Not rounded = - 24.024024024024%
Rounded off to max. 2 decimal places ≈ - 24.02%
The absolute (actual) difference
33.3 - 41.3 = - 8
By what percentage has 33.3 decreased?
Answer: By ≈ - 24.02%
By what percentage is 41.3 smaller than 33.3?
Answer: By ≈ - 24.02%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).