**4.1 Clinician prediction of survival (CPS)**

Clinician prediction of survival (CPS) is a quick and convenient estimate of survival based on clinical experience and intuition. While CPS is convenient, it is inaccurate and subject to biases with consistent over estimation of survival. Literature review suggests CPS is accurate 20–30% of the time with ~80% of prognostic errors being overoptimistic [33]. Overestimation may lead to overtreatment and delayed referrals to palliative care. Conversely, while less common, underestimation can result in undertreatment and premature referral to hospice or supportive services [33]. CPS can be classified by several approaches. The most common technique utilized by clinicians is a temporal approach which attempts to answer "How long will the patient live?" or providing an estimated duration of survival [32]. A probabilistic approach estimates "What is the probability of survival in a specific time frame?" (i.e. 30% chance of being alive in 6 months) [32]. Alternatively, the surprise question is utilized to determine "Would I be surprised if a patient died in the next year?" [34]. The surprise question significantly improves clinician accuracy in predicting poor prognosis. In order to provide the most accurate prognosis several models have been developed to facilitate clinical communication. While these validated models provide more objective prognosis, they do not necessarily capture the nuances of an individual's health.
