1. No-one has access to the actual “re-offend” rates: all we have is “re-arrest,” “re-convict,” or at best “observed and reported re-offence” rates.
2. A-priori we do not expect the amount of melanin in a person’s skin, or the word they write down on a form next to the prompt “Race” to be correlated with the risk of re-offense. So, any tool that looks at “a bunch of factors” and comes up with “Black people are more likely to re-offend” is “biased” compared to our prior (even if our prior is wrong).
If you create a new twitter account (and make the first tweet(s) include your name and some quotes from the intro of https://books.google.com/books/about/The_Prophecies.html?id=neZvDwAAQBAJ&printsec=frontcover&source=kp_read_button ) and then put all your predictions, and only your predictions, in it—that would be an easy time stamped record.