How the numbers are produced.

1. Formulas live in code, not in prose

Every calculation is implemented as a tested function in a service module. Templates never contain arithmetic. This means a result can be reproduced, unit-tested and compared against a known reference — and it means a change to a formula is a visible, reviewable change.

Loan and payment formulas use exact decimal semantics where currency is involved, and each calculator has automated tests covering zero, negative, extreme and missing inputs.

2. Scoring is weighted and explainable

A Pearto Score is composed from criteria. Each criterion has:

• A raw value — the underlying measurement or rating.
• A normalised value — that measurement mapped onto a 0–100 scale.
• A weight — how much you said this criterion matters.
• A contribution — the normalised value multiplied by the weight.

The score is the weighted total. Because contributions are shown individually, you can always see which criterion moved the result — and you can change its weight if you disagree with the default.

3. Confidence is reported, not implied

Confidence reflects the separation between options and the completeness of your inputs. It is deliberately blunt:

• High — the options are clearly separated and the key inputs were supplied.
• Medium — the outcome depends on assumptions that could reasonably be wrong.
• Low — important inputs are missing, so the result is indicative only.

A confidence level is a statement about the quality of the comparison, not a guarantee about the future.

4. Assumptions are always visible

When a value is unknown, Pearto does not quietly pick one. It uses a typical value, marks it as an assumption, and lists it with the result. Typical values are derived from published ranges and are reviewed periodically. Changing an assumption is always possible.

5. Sensitivity, break-evens and flip points

For each decision Pearto works out which single variable would most easily reverse the recommendation, and at what value it would reverse. These are the flip points. They are often more useful than the score itself: they tell you what to watch, and what to research next.

6. Currency, rounding and precision

Currency values are computed with decimal arithmetic and rounded only for display. Percentages are stored at full precision and formatted at output. Reported totals may not add exactly due to rounding of the displayed components; the underlying calculation is unaffected.

7. Jurisdiction and local variation

Many everyday decisions depend on local rules — tax treatment, closing costs, cooling-off periods, late-fee regulation. Where a result depends on jurisdiction and no local data is available, Pearto says so instead of assuming a location. You should verify anything jurisdiction-dependent with the relevant authority or a qualified professional.

8. Review and freshness

Assumptions and reference values carry a review date. Anything past its review date is treated as stale and surfaced for review rather than presented as current. Pearto never claims real-time data unless a live source is actually connected.

9. Limits

Pearto models financial and practical tradeoffs. It does not model individual risk tolerance, health, relationships or values beyond the weights you set. It is a decision-support tool, not financial, legal, medical or tax advice.