Which source the index uses for each kind of claim

Each kind of claim on this site has one source that owns it. Health Canada owns health guidance, C-NRPP owns certification, the Cross-Canada Radon Survey owns prevalence, statutes and regulators own rules, and program administrators own funding. Within each, the newest dated edition wins, and when two credible sources disagree, the page names both, gives their dates and says which one we used. See how every number on the site is labelled and dated.

Health guidance comes from Health Canada first

Health Canada sets the radon guideline, so health guidance starts there. For every other claim, the organization whose remit includes it comes first.

• Health Canada sets the guideline and recommends C-NRPP certified mitigation contractors, but does not certify or license them.
• C-NRPP, the Canadian National Radon Proficiency Program, is the certification radon professionals hold, and runs the national testing program for consumer monitors.
• CARST, the Canadian Association of Radon Scientists and Technologists, is a nonprofit professional association that states it oversees C-NRPP.
• Take Action on Radon is a national awareness initiative funded by Health Canada.

Certification is voluntary; there is no national radon contractor licence. We sort sources into four tiers by what each is set up to provide.

• Tier 1, government and intergovernmental bodies, such as Health Canada and Statistics Canada: health guidance, statistics, legislation, codes and programs.
• Tier 2, research and science: peer-reviewed research, universities and the Cross-Canada Radon Survey working group.
• Tier 3, standards, certification and public programs, such as C-NRPP and CARST: each for what it provides, never as a government health authority.
• Tier 4, commercial sources: products, services or pricing, never the sole source for health risk, prevalence or guidelines.

Read what Health Canada’s guideline says. See what the C-NRPP certifications are and how to check one.

Primary sources outrank secondary reporting

For prevalence we cite the survey report itself. The Cross-Canada Survey of Radon Exposure in the Residential Buildings of Urban and Rural Communities, 2024 Report, Version 1.1, was released in October 2024. The Evict Radon National Study team produced it with Health Canada, CAREX Canada and the BC Centre for Disease Control.

Never primary evidence here:

• Mitigation and testing company blogs.
• Manufacturer marketing pages and test kit retailers.
• Home service directories and lead generation sites.
• Real estate and insurance marketing pages.
• Roundup articles with no named primary source.

Being right on one subject does not make a source right on another, so we judge the source against the claim, not against its reputation. The Canadian Lung Association sells test kits, and its page carries guidance that Health Canada has since replaced. We cite it for its own programs, not on devices, testing or interpretation. Tarion is authoritative on Ontario’s new home warranty, not on retest intervals.

Competitor figures are never published, and vendor-funded or non-public sources are not used for published facts. See what the 2024 survey found and how it compares with 2012. See which consumer monitors C-NRPP lists and which are recalled.

When sources conflict, we compare their methods and say which we used

When credible sources disagree, we name them, give their dates, and explain the difference where we can. We use the newest dated primary edition and do not blend incompatible figures or pick the most alarming one. A Health Canada fact that rests on a secondary source is traced to the primary or left out.

Health Canada’s two live prevalence pages show why every prevalence claim names its page and date. Its action guide for provinces and territories cites the 2024 survey’s “about 1 in 5 homes”. Its action guide for municipalities still says “about 7%”.

Commercial involvement does not invalidate research, and hiding it would be worse than naming it. The 2024 survey names the organizations that supplied source data, including Radonova and provincial lung associations. The Evict Radon National Study sells test kits to fund its research; we cite its findings, not its store. CARST, an association of radon professionals, states that it oversees C-NRPP, and we treat the registry as a registry. See the site’s commercial relationships.

Every claim links to the source it came from

Every statistic on this site carries its source and the date we checked it. Every link is stored without tracking parameters. We keep the register of sources as a dataset, built from the same records the pages read, and publish it as it is entered. If a claim looks wrong to you, tell us and we will check it against the record. See how to report a claim you think is wrong.