How I remember it from the lecture, the three risk factors are Severity (S), occurrence (O), and noticeability (N) or S.O.N. The product of the numerical values for these three factors is how the Risk Priority Number (RPN) is assigned. For my analogy, you would want to minimize the amount of risks you would both want to take with your son and want your son to take. Similarly, you want to lower the severity, occurrence, and/or noticeability of the risk in order to lower the RPN. The lower you can get the RPN number, the better off you are.