Table 1.

Linear rates of speed improvement estimated from datasets from model 1. Parameter estimates are from REML models with year fitted as continuous covariate. Inference is by likelihood comparison of full and reduced models fitted by ML (see text for details).

dataset	years	classes	finishers	distance (furlongs)	temporal trend ± s.e. (yards s−1 year−1)		p
1.1	1850–2012	elite	winners	5–7	0.014 ± 5 × 10−4	659	<0.001
1.2	1850–2012	elite	winners	8–12	0.013 ± 4 × 10−4	677	<0.001
1.3	1850–2012	elite	winners	14–20	0.011 ± 0.001	106	<0.001
1.4	1997–2012	elite	winners	5–7	0.020 ± 0.002	64.3	<0.001
1.5	1997–2012	elite	winners	8–12	0.006 ± 0.002	5.8077	0.016
1.6	1997–2012	elite	winners	14–20	0.007 ± 0.005	2.71	0.100
1.7	1997–2012	elite	all	5–7	0.023 ± 0.001	409	<0.001
1.8	1997–2012	elite	all	8–12	0.006 ± 0.001	26.0	<0.001
1.9	1997–2012	elite	all	14–20	0.008 ± 0.002	12.3	<0.001
1.10	1997–2012	all	winners	5–7	0.014 ± 6 × 10−4	466	<0.001
1.11	1997–2012	all	winners	8–12	0.006 ± 7 × 10−4	70.6	<0.001
1.12	1997–2012	all	winners	14–20	0.005 ± 0.002	11.2	<0.001
1.13	1997–2012	all	all	5–7	0.018 ± 4 × 10−4	2212	<0.001
1.14	1997–2012	all	all	8–12	0.010 ± 4 × 10−4	634	<0.001
1.15	1997–2012	all	all	14–20	0.009 ± 8 × 10−4	114	<0.001