~/tools/percentage-points-vs-percent $ run stats --compare-percentage-points
Percentage Points vs. Percent Change
Compare absolute percentage-point shifts and relative percentage changes side-by-side.
An interest rate going from 5% to 8% represents an increase of 3 percentage points (absolute subtraction), but is a 60% relative percentage increase in the rate itself.
Percentage-Point Difference:
+3 pp
(8% - 5%) = 3 percentage points
Relative Percent Change:
+60%
((8% - 5%) / 5%) × 100 = 60%
// Decoupling Absolute Points vs Relative Changes
In commercial broadcasting, financial journalism, and banking, percentages themselves represent rates. When a rate shifts, stating that the rate increased by "3%" is highly ambiguous and technically incorrect. Using the term "percentage points" clarifies the exact absolute arithmetic change.
Mathematical Formulas:
Percentage Points Difference = P2 - P1
Relative Percentage Change = ((P2 - P1) / P1) × 100
Worked Example: Interest rate going from 5% to 8%
Let's apply the formulas to the classic interest rate example:
1. Absolute Difference: 8% - 5% = 3%. We describe this as an increase of 3 percentage points (abbreviated as pp).
2. Relative Change: (3 / 5) × 100 = 0.60 × 100 = 60%.
The interest rate went up by 3 percentage points, representing a 60% relative increase in interest costs!
// Frequently Asked Questions
▸Why is saying 'interest rates increased by 3%' incorrect?
If an interest rate is 5% and you increase it by a relative 3%, the new rate is 5% * 1.03 = 5.15%. If the rate becomes 8%, the rate itself grew by a massive 60%! Saying 'percentage points' avoids this critical ambiguity.
▸What is the abbreviation for percentage points?
Percentage points are commonly abbreviated as 'pp', 'p.p.', or sometimes referred to as 'percentage-point shift'.
▸Where is this comparison most commonly used?
It is standard in financial reporting (central bank interest rate adjustments), political polling (changes in candidate support ratings), and statistical research reports.