Table 1.

Effects associated with covariates appearing in the nested frailty model

Covariate	HR (90% CI)	p value	Inference	% likelihood effect is beneficial |trivial| harmful
Age (2 SDs = 8 y)	1.03 (0.98–1.09)	0.32	Very likely trivial	0 |99| 1
Height (2 SDs = 15 cm)	1.05 (0.99–1.13)	0.19	Likely trivial	0 |93| 7
Mass (2 SDs = 26 kg)	1.02 (0.95–1.11)	0.62	Likely trivial	0 |95| 5
Positional group (reference = ‘Backs’)	0.91 (0.85–0.98)	0.04	Possibly trivial	39 |61| 0
Number of previous injuries (2 SDs = six injuries)	1.28 (1.15–1.41)	0.0001	Very likely harmful	0 |1| 99

CI confidence interval, HR hazard ratio, SD standard deviation