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 = 56.7, v2 = 64.9.
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: - 61.
- Choose a random positive number for the end value: 75.
Formula and calculation:
(v1 - v2) / v1 =
(- 61 - 75) / - 61 =
-136 / - 61 ≈
2.229508196721 ≈
2.23
Although the absolute difference is negative: -136, the relative decrease change is positive: 2.23. 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:
(56.7 - 64.9)/|56.7| =
- 8.2/56.7 =
- 8.2 ÷ 56.7 =
- 8.2 ÷ 56.7 × 100/100 =
(- 8.2 × 100 ÷ 56.7)/100 =
(- 820 ÷ 56.7)/100 ≈
- 14.462081128748/100 =
- 14.462081128748% ≈
- 14.46%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 56.7 to the final, end value 64.9:
Rounded off to max. 12 decimal places ≈ - 14.462081128748%
Rounded off to max. 2 decimal places ≈ - 14.46%
The absolute (actual) difference
56.7 - 64.9 = - 8.2
By what percentage has 56.7 decreased?
Answer: By ≈ - 14.46%
By what percentage is 64.9 smaller than 56.7?
Answer: By ≈ - 14.46%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).