Table 2.

Proportion of STarT-Back and POP samples classified as low, medium and high risk of poor outcome according to STarT-Back^a criteria at baseline.

Risk	STarT-Back derivation sample (N = 131) (%)	STarT-Back validation sample (N = 500) (%)	POP baseline (N = 598) (%)
Low	40	47	32.3
Medium	35	38	45.8
High	25	15	21.9

^aHill et al., 2008.