What exactly lowers stealth score?

A few things that lowers the score include: Destroying any lights at all, which penalizes you with 2% off per light destroyed, same goes for locks destroyed also, 5% off the score per guard knocked out, or possibly killed, its the same for knocking out or killing civilians, in a nutshell, you are REQUIRED to ghost the entire level or else you wont get 100% stealth score, no touching anyone at all. Always use the OCP to disable lights,dont get spotted or seen as an intruder, EVER. Which means, lasers, cameras, and guards absolutely cannot spot you once, if that happens, its an automatic -15% stealth score, but that is all i can find out.