An important factor of determining the value of the risk index is the tolerability of the risk. Often low risks such as mild discomfort associated with the use of the device can receive a low index number even if the chance of occurrence is very high. In this situation both the tolerability and severity of risk make the risk index low. However, if the patient is a child or a toddler, discomfort can impact the completion of treatment and therefore the tolerability of the risk is decreased resulting in a higher risk index.