1. 100% does not exist. 2. Even if it did, there are too many variables to take into consideration. Any calculation would be flawed and incomplete. 3. Although an individual's behavioral patterns can be observed and therefore predicted, psychology is not a perfect science. The human psyche is both fragile and remarkable fragile. A crack is sometimes more easily noticed than severe trauma. And we are products of severe trauma. All it takes is for one of us to have a breakdown, and who knows what the fuck could happen?