FICO to incorporate buy-now-pay-later loans into credit scores

FICO scores are a joke. They hint at what they use to calculate them, but the algorithms are kept secret. Fair Isaac can't reveal the algorithms, otherwise they'd get gamed. Incentives to keep bad info and wrong info in dossiers are strong, too. If allowed, Fair Isaac would put rumors and other bullshit on n your file, and never take it out.

the score is easy to reverse engineer if you have the data and pretty much every big bank has the data.

source: I worked at a big bank and did this, it was easy.

Most of the stuff is obvious and intuitive (don't make late payments). One that's not terribly intuitive is credit line utilization. It has a big impact and most people don't think about it. For example, it's better to have 2k in credit card debt if you have 20k in credit lines vs. 1k in debt on 2k in credit lines.