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 = 10.5, v2 = 47.9.
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: - 78.
- Choose a random positive number for the end value: 94.
Formula and calculation:
(v1 - v2) / v1 =
(- 78 - 94) / - 78 =
-172 / - 78 ≈
2.205128205128 ≈
2.21
Although the absolute difference is negative: -172, the relative decrease change is positive: 2.21. 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:
(10.5 - 47.9)/|10.5| =
- 37.4/10.5 =
- 37.4 ÷ 10.5 =
- 37.4 ÷ 10.5 × 100/100 =
(- 37.4 × 100 ÷ 10.5)/100 =
(- 3,740 ÷ 10.5)/100 ≈
- 356.190476190476/100 =
- 356.190476190476% ≈
- 356.19%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 10.5 to the final, end value 47.9:
Rounded off to max. 12 decimal places ≈ - 356.190476190476%
Rounded off to max. 2 decimal places ≈ - 356.19%
The absolute (actual) difference
10.5 - 47.9 = - 37.4
By what percentage has 10.5 decreased?
Answer: By ≈ - 356.19%
By what percentage is 47.9 smaller than 10.5?
Answer: By ≈ - 356.19%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).