A post on Fair Ivy is built from public sources, and every source is linked. Numbers that are guesses are labelled as guesses, and each post is checked against its sources before it goes up.
Sources
The facts come from pages anyone can open: regulators, laws, company reports, named news stories. They're linked in the post and listed at the bottom, so you can go and look. If sources disagree or one is weak, the post says so.
Guesses
Plenty of business numbers are hard to find. When that happens, a post says it couldn't find the number, or it gives my rough guess and how I got there. Numbers in the drawings follow the same rule. Worked examples are plainly hypothetical: "say a clinic with two chairs".
The Field Guide takes its numbers from the posts and marks each one as sourced or my guess, and every receipt on the Napkin is made up to show the sum.
The check
Before a post goes up, its claims are checked against the sources they came from. A claim that doesn't hold up gets fixed or comes out.
Opinions
"I think" and "I'd walk away" are opinion, and you're free to disagree. If you spot a mistake, see corrections. If money is involved, disclosure covers it.