How we verify every number

Every statistic on The Longevity Ledger comes from a peer-reviewed paper by researchers at a major university. Before anything is published, it has to pass four checks. If it fails any one of them, it does not run.

Where the research comes from

We search open databases of published science for new studies on aging, lifespan and health. We only use open-access papers, so we can read the full text, and so can you.

Check 1: Is the research real?

• The paper's DOI must resolve, and its title, authors and year must match the publisher's record.
• The paper must be peer reviewed and must not be retracted.
• At least one author must work at one of the 300 most-cited universities or research hospitals in the world, ranked by OpenAlex and refreshed monthly.
• Every number we quote must appear word for word in the paper's full text.
• If we calculate a new number from the paper, a computer redoes the math. We show the math on the page.
• We say whether the study looked at people or animals, and whether it shows cause or only a link.

Check 2: Is it written clearly?

Every article must read at a grade 6 level or easier. We scan for vague claims, hype and filler. No number may appear in the article unless it is traced to the paper.

Check 3: Does it answer a real question?

We name the readers most likely to care about the finding, then check that real people search for it. The headline, opening and page address use the words those readers actually use.

Check 4: Is the page built right?

Each page must have one main headline, clear section headings, a labeled figure built from the study's data, working source links, and descriptions for every image.

How the articles are made

Articles are drafted with the help of AI writing tools, edited against Wikipedia's published guide to the signs of AI writing, fact-checked claim by claim against the paper's full text, then held to the checks above by automated review, under the editorial direction of K. Helm. Each article lists the date it passed every check.

Corrections

When we get something wrong, we fix it on the page, show what changed, and list it on our corrections page.

What we are not

We report on research. We are not doctors and we do not give medical advice. One study is never the final word.