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 = 241, v2 = 400.8.
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: - 31.
- Choose a random positive number for the end value: 51.
Formula and calculation:
(v1 - v2) / v1 =
(- 31 - 51) / - 31 =
-82 / - 31 ≈
2.645161290323 ≈
2.65
Although the absolute difference is negative: -82, the relative decrease change is positive: 2.65. 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:
(241 - 400.8)/|241| =
- 159.8/241 =
- 159.8 ÷ 241 =
- 159.8 ÷ 241 × 100/100 =
(- 159.8 × 100 ÷ 241)/100 =
(- 15,980 ÷ 241)/100 ≈
- 66.307053941909/100 =
- 66.307053941909% ≈
- 66.31%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 241 to the final, end value 400.8:
Rounded off to max. 12 decimal places ≈ - 66.307053941909%
Rounded off to max. 2 decimal places ≈ - 66.31%
The absolute (actual) difference
241 - 400.8 = - 159.8
By what percentage has 241 decreased?
Answer: By ≈ - 66.31%
By what percentage is 400.8 smaller than 241?
Answer: By ≈ - 66.31%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).