Percentage Points vs Relative Change Precision Guide
Core Distinction
- Δ Percentage Points: New − Old (absolute difference)
- Percentage Change: (New − Old)/Old ×100
Usage Rules
- Communicate rate moves (interest, unemployment, turnout) in points
- Communicate growth / improvement magnitude in percent change
- Avoid mixing: “Up 2 percentage points” NOT “Up 2%” when from 3%→5%
Interpretation Examples
- 3% → 5%: +2 pp; +66.67% relative
- 40% → 44%: +4 pp; +10% relative
- 75% → 70%: −5 pp; −6.67% relative
Communication Risk Flags
- Headline inflation: “Interest doubled” (should specify points vs relative)
- Political stats misread when relative framed as absolute
Impact Modeling
- Payment delta ≈ Loan × (Δrate/12) (simplified first‑order for mortgages)
- Revenue rate metrics use points for margin spread expansion clarity
FAQ
- Why both? One shows pure numeric difference; the other contextual proportional shift.
- Can points be decimal? Yes: move 6.25%→6.50% = 0.25 pp.
- Best reporting order? State points first, then relative % if material.
Action Tip: In data tables provide twin columns (Δpp, %Δ) to eliminate ambiguity in trend discussions.
Context |
| 5% | 10% | +5 pp | +100% | Interest rate increase |
| 20% | 25% | +5 pp | +25% | Tax rate change |
| 60% | 65% | +5 pp | +8.33% | Approval rating |
| 15% | 10% | -5 pp | -33.33% | Unemployment drop |
| 3% | 3.5% | +0.5 pp | +16.67% | GDP growth |
| 12% | 8% | -4 pp | -33.33% | Inflation decrease |