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 = 95.7, v2 = 77.2.
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: - 34.
- Choose a random positive number for the end value: 69.
Formula and calculation:
(v1 - v2) / v1 =
(- 34 - 69) / - 34 =
-103 / - 34 ≈
3.029411764706 ≈
3.03
Although the absolute difference is negative: -103, the relative decrease change is positive: 3.03. 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:
(95.7 - 77.2)/|95.7| =
18.5/95.7 =
18.5 ÷ 95.7 =
18.5 ÷ 95.7 × 100/100 =
(18.5 × 100 ÷ 95.7)/100 =
(1,850 ÷ 95.7)/100 ≈
19.331243469175/100 =
19.331243469175% ≈
19.33%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 95.7 to the final, end value 77.2:
Rounded off to max. 12 decimal places ≈ 19.331243469175%
Rounded off to max. 2 decimal places ≈ 19.33%
The absolute (actual) difference
95.7 - 77.2 = 18.5
By what percentage has 95.7 decreased?
Answer: By ≈ 19.33%
By what percentage is 77.2 smaller than 95.7?
Answer: By ≈ 19.33%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).