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 = 1,930, v2 = 821.5.
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: - 80.
- Choose a random positive number for the end value: 83.
Formula and calculation:
(v1 - v2) / v1 =
(- 80 - 83) / - 80 =
-163 / - 80 =
2.0375 ≈
2.04
Although the absolute difference is negative: -163, the relative decrease change is positive: 2.04. 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:
(1,930 - 821.5)/|1,930| =
1,108.5/1,930 =
1,108.5 ÷ 1,930 =
1,108.5 ÷ 1,930 × 100/100 =
(1,108.5 × 100 ÷ 1,930)/100 =
(110,850 ÷ 1,930)/100 ≈
57.435233160622/100 =
57.435233160622% ≈
57.44%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 1,930 to the final, end value 821.5:
Rounded off to max. 12 decimal places ≈ 57.435233160622%
Rounded off to max. 2 decimal places ≈ 57.44%
The absolute (actual) difference
1,930 - 821.5 = 1,108.5
By what percentage has 1,930 decreased?
Answer: By ≈ 57.44%
By what percentage is 821.5 smaller than 1,930?
Answer: By ≈ 57.44%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).