01
Active voice. Second person where it helps.
Active sentences are 30% shorter and easier to parse under pressure.
Avoid
The bioswale is estimated to potentially retain stormwater volumes.
Use
The bioswale holds 540 m³ of stormwater each year.
Write so a CFO and an ecologist read the same number the same way.
Six rules. Apply them on every label, tooltip, button, chart caption and report sentence. When a rule conflicts with brevity, brevity wins; when it conflicts with sourcing, sourcing wins.
The test
If a borough councillor and a flood engineer can both quote your sentence in a meeting tomorrow without changing a word, it passes.
02
Numbers before adjectives.
Decision-makers act on magnitudes, not feelings.
Avoid
Significant cooling effect during heatwaves.
Use
Cuts peak street heat by 2.1°C on a heatwave day.
03
No jargon without a one-line gloss.
Clients are mixed audiences. Glossaries belong inline, not at the end.
Avoid
UTCI delta of −2.1°C exceeds RCP 4.5 thresholds.
Use
Universal Thermal Climate Index drops 2.1°C — the difference between 'hot' and 'very hot' on the WHO scale.
04
One sentence per idea. Twenty-two words or fewer.
Long sentences hide the verdict. Short sentences force a verdict.
Avoid
Across the modelled 10-year horizon, considering Monte Carlo uncertainty bands and Defra Green Book discounting, the project demonstrates positive net present value.
Use
Over 10 years, the project pays back £1.24M after costs. Confidence: high.
05
Verbs of consequence, not buttons.
Generic verbs leak credibility. Every CTA earns its place.
Avoid
Submit · OK · Click here · Go · Save
Use
Run resilience model · Calculate avoided costs · Compose client brief · Export dossier
06
Source every number, in line.
Procurement teams reject numbers without provenance. Make sourcing the default state, not a footnote.
Avoid
BNG +14.3 units.
Use
BNG +14.3 units (Defra Metric v4.0, baseline survey 2025-04, ±1.2 unit confidence).
Words and CTAs we don't ship.
The voice-lint script (scripts/voice-lint.ts) flags these in JSX text. Replace with verbs of consequence and quantified claims.
SubmitOKGoClick hereClickMore infoLearn moreSaveSignificantRobustLeverageSynergyEmpowerCutting-edgeWorld-classBest-in-classSolutions
Every metric gets a one-line read.
Use <PlainRead> above any number a non-specialist needs to act on. Hide the methodology behind the disclosure — never lead with it.
What this means
The project pays back £1.24M more than it costs over 10 years. A financier would call this a 4.6× return.
What this means
Habitat value rises by +14.3 units — enough to offset a small commercial development under BNG rules, with one survey caveat.