How facts work
In plain termsEvery number on this site is a cell. A cell has four fields. When the cell goes stale we hide the number rather than quote expired law with a straight face.
- Fact cells
- 1952
- Primary texts
- 67
- High-vol window
- 3 mo
- Last verified
- 2026-08
Dataset v0.16.32. Empty fields are omitted for guests. Two deep pillars — stay and tax — beat a forest of thin tip pages.
The four fields
Take Vietnam's tax-residence line. Stay 183 days in a tax year and you are a resident for personal income tax — PIT, the tax on what you earn. That single figure is stored like this.
- Value
- 183 daysDay-count threshold for Vietnam tax residence
- Source
- Luật Thuế TNCN 109/2025/QH15 Điều 2 khoản 2 điểm a; NĐ 253/2026/NĐ-CP Điều 4 khoản 1 Open the gazette
- Checked
- 2026-08Status now: fresh. Age is counted in months because the corpus does not invent a day.
- Volatility
- lowLow-volatility statute. Refresh window 24 months. Hide the number after 48 months.
The same anatomy sits behind every figure you see — a visa fee, a treaty day-count, a work-permit salary floor. The page never prints a number that does not have all four fields.
Three bands, one hide rule
Volatility is how fast that kind of fact moves. The window lives in the dataset so we change a limit by editing data, not code.
| Band | Window | Hide after | What lives here |
|---|---|---|---|
| High | 3 months | 6 months | Fees, salary floors, exemption thresholds that ministries move often. |
| Medium | 6 months | 12 months | Counting rules, form numbers, administrative practice. |
| Low | 24 months | 48 months | Statute text and treaty articles that sit for years. |
- Fresh — inside the window. The number shows.
- Verifying — past one window, still inside two. The number still shows, with a verifying tag, so we have time to re-open the gazette without the page going blank overnight.
- Unverified — past two windows. The number is replaced by a dash. The calculator refuses to compute. We would rather show a blank than quote expired law with confidence.
Why two thresholds, not oneJumping from “trusted” to “hidden” in a single month trains us to switch the rule off.
A high-volatility fee checked in August is still fresh in November. In December it picks up the verifying tag. In March it disappears, after more than two three-month windows. Those middle months are the reminder to re-read the circular — not a licence to keep quoting it forever.
The 183-day cell above is low volatility. Checked 2026-08, it stays on the page until 24 months have passed, and only hides after 48. A treaty article does not need the same nervousness as a visa fee.
A high-volatility cell, openedStatutory TRC fee — Temporary Residence Card, the plastic that lets you stay past a visa stamp.
- Value
- 145 USDStatutory fee for TRC up to 2 years
- Source
- TT 28/2026/TT-BTC Biểu Mục II số 5a (HL 01/4/2026)
- Checked
- 2026-08
- Volatility
- high — window 3 months, hide after 6.
Fees move. That is why this cell is high volatility and the 183-day line is not. Same machinery, different clock.
When two official sources disagreeWe file a conflict cell. We do not pick a winner to look tidy.
Singapore's IRAS treaty text and the Philippines BIR register disagree on the year the Singapore–Philippines treaty took effect. Both are official. The overlay keeps both dates on the page instead of averaging them into a fake certainty.
Open the conflict on the pair page. The same honesty rule applies anywhere two gazettes will not line up.
What this site will not do
- Quote a secondary blog, a forum screenshot, or an agency brochure as a fact cell.
- Invent a day of the month when the corpus only knows the month.
- Keep showing a number after twice its refresh window.
- Let the calculator compute on a stale required parameter.
Next doors
Common questions
Why hide a number instead of leaving it up with a warning?
A stale figure with a warning still looks like a figure. People quote it. Past twice the refresh window we hide the value and the calculator refuses to compute, so nobody can copy an expired rule with our confidence attached.
What is a check month?
The month we last opened the primary text and confirmed the cell still matches. The corpus only records months, never a fake day, because a law gazette rarely tells us the hour we read it.
What does high, medium and low volatility mean?
How fast that kind of fact moves. Fees and salary floors are high — they change in months. Day-count rules in a statute are low — they sit for years. The window is stored with the data, not hardcoded in the page.
What happens when two official sources disagree?
We file a conflict cell and keep both dates visible. We do not pick a winner to look tidy. The Singapore–Philippines treaty page is the worked example.