# Methodology

> How the numbers on every PetGuideCalc tool are built and reviewed.

## What every tool has in common

Every calculator on PetGuideCalc ships with five things, in this order:

1. **A named standard.** The primary source the formula comes from — usually a veterinary guideline, a peer-reviewed paper, or a published care standard. Named inline, not hidden in a footnote.
2. **The formula.** Either the closed-form equation (for example, `RER = 70 × BW^0.75`) or the lookup table the calculator runs against.
3. **An accuracy statement.** What is exact, what is a range, what is an estimate. The page says which it is.
4. **A verification hint.** What the user can measure to confirm the result — for example, "verify with a Solarmeter 6.5" for UV index.
5. **A review date.** When the tool was last checked against the source literature, surfaced in the tool card.

## Standards we cite most often

The full enumeration lives on [/sources/](/sources/). The most-cited standards, by category:

- **Reptile lighting & temperature** — Baines 2016 Ferguson zones, ReptiFiles species care articles, Arcadia published decay curves for T5 HO and T8 UVB tubes.
- **Aquarium stocking & filtration** — SeriouslyFish species profiles, FishBase community-tank rules, standard community-tank temperature bands.
- **Small-pet husbandry** — RSPCA hamster cage standards (≥15 cm bedding, 80 × 50 cm Syrian floor area), PDSA welfare sheets, House Rabbit Society diet references.
- **Pet nutrition & energy** — NRC 2006 "Nutrient Requirements of Dogs and Cats", WSAVA Global Nutrition Guidelines for the RER/MER formula.
- **Veterinary drug dosing** — Merck Veterinary Manual dosage-calculation section, WSAVA Therapeutic Guidelines, Plumb's Veterinary Drug Handbook (ISBN 9781118911158).

## Editorial review cadence

Tools are reviewed when any of the following triggers fires:

- A source standard publishes an update (e.g., a new edition of a veterinary formulary).
- A peer-reviewer engagement flags a specific tool page.
- A reader reports a calculation that disagrees with a published reference — checked within 7 days.
- Every 12 months as a routine refresh, even without other triggers.

An automated check verifies that no citation ships with a broken DOI or PMID; it runs on every pull request before anything is published.

## Honest limits

Three categories of result are deliberately labeled rather than smoothed over:

- **Cross-species approximations.** Where a standard covers one species and the calculator is asked about another, the result is marked "approximation" inline. We don't extrapolate silently.
- **Estimates vs. measurements.** Where the calculator uses a heuristic (e.g., wattage as a proxy for UVB output class), the page names the proxy and tells you what to measure to upgrade the result.
- **Out-of-scope claims.** Anything we cannot support with a named source is left out — not presented with hedging language. The drugs/medication tool explicitly disclaims prescribing. The vet-disclaimer is on every page footer.

## Questions about our methodology

**Where do the formulas come from?** Every formula on the site is named on its tool page with the published source. The most-cited standards are WSAVA (World Small Animal Veterinary Association) Global Nutrition Guidelines for the RER/MER formulas, NRC 2006 "Nutrient Requirements of Dogs and Cats" for canine and feline energy, Ferguson-zone UV exposure guides for reptile lighting, RSPCA care standards for small pets, and ReptiFiles species care articles for reptile husbandry. Full enumeration on [/sources/](/sources/).

**How accurate are the calculators?** Where a standard gives a single number (e.g., RER = 70 × BW^0.75), the calculator returns that value to full floating-point precision. Where a standard gives a range (e.g., basking UVI 3.0–6.0 for bearded dragons), the calculator returns the published range and lets you see where in it you fall. Where a value is an estimate rather than a measurement, the page tells you so and names what to verify.

**How are cross-species approximations handled?** Where a standard is published for one species and a calculator applies it to another, the result is labeled as a cross-species approximation — never presented as a species-specific value. The UVB calculator lists which species are directly supported (six, as of 2026-08) and marks any other input as a generalized estimate.

**How often are the tools reviewed?** Every tool page carries a "Reviewed YYYY-MM" date in the entry card. Tools are re-reviewed when the source standards update or when peer-reviewer feedback arrives. An automated citation check runs before every publish and blocks any tool that would ship with a broken DOI, empty author, or fabricated publication date.

**What happens when a source contradicts another?** The calculator surfaces both ranges and names which standard each one is from. The UVB calculator, for example, cites both the Ferguson-zone framework (Baines 2016) and per-species target UVI bands from ReptiFiles and Arcadia. When the two diverge for a given species, both are shown with a note.