Where the numbers come from
We start from the organizations that collect the data: statistics agencies such as the Bureau of Transportation Statistics and the Bureau of Labor Statistics, regulators, tax authorities and the annual filings of listed companies. When a figure only exists in a commercial source, such as a fare search site, we say so on the page.
We cite the original publication, not a news story or a website that repeats it. If we cannot reach the original, we leave the number out.
How we cite
Every figure on a research page carries a small footnote number that links to the source list at the end of the page. Each source is listed once, with its publisher, title, date and link.
Our own calculations
Averages, totals, shares and trend lines that we compute ourselves are labeled as our calculation, and the method is described on the same page. A trend line extended into the future is marked "Our calculation, not a forecast" and states the years it was fitted on.
Checked before publishing
Before a page is published, every number is checked against the saved copy of its source, every calculation is repeated, and the page is reviewed by someone who did not write it. The same checks run again each time a page is updated.
Updates and corrections
We update pages when a newer release of the data comes out; the date at the top of each page shows the last update. If you find an error, tell us. We correct it and note the change on the page.
Reuse and citation
Our charts, tables and data are free to reuse under the Creative Commons Attribution 4.0 license. Please name Travel Statistics Bureau and link to the page. Each research page has a "Cite this page" button that copies the site name, page title and address.
Independence
Travel Statistics Bureau is a not-for-profit, independent project run by volunteers. It is free to use; contributions cover hosting and running costs. No company pays for, reviews or approves what we publish.