Several different performance status metrics have been developed to quantify performance status, and among them, the Karnofsky performance status (KPS) is the most often used. The KPS ranges from values of 100, signifying normal functional status with no complaints nor evidence of disease, to zero, signifying death. The complete spectrum of values for the KPS scale is reproduced below.

Multiple studies have reported associations between patients’ performance status and their subsequent survival with lower performance status predicting shorter survivals. The size of the association is described differently in different studies depending on the statistical methods used, but several studies report that among patients enrolled in palliative care programs, a KPS of less than 50% suggests a life expectancy of fewer than 8 weeks (Evans 1985, Maltoni 1994,1995, Reuben 1988, Morita 1999, Llobera 2000).

The association between KPS value and survival in patients enrolled in palliative care programs is described in the table below.