Table 4.

Effect of travel direction on the impact of jet lag on home and away aggregate defensive performance

	Home jet lag					Away jet lag
Defense	West	West P value	Average	East	East P value	West	West P value	Average	East	East P value
Runs allowed	−0.083 ± 0.106	0.7825	4.652 ± 0.015	0.197 ± 0.124	0.0555	0.069 ± 0.084	0.2075	4.787 ± 0.015	0.162 ± 0.093	0.041*
Batting average	−0.002 ± 0.003	0.8135	0.254 ± 0.0003	0.003 ± 0.003	0.198	0.002 ± 0.002	0.1525	0.265 ± 0.0004	0.003 ± 0.002	0.095
On-base, %	−0.004 ± 0.003	0.925	0.319 ± 0.0004	0.003 ± 0.003	0.209	0.005 ± 0.002	0.0205*	0.334 ± 0.0004	0.002 ± 0.002	0.17
Slugging, %	−0.002 ± 0.005	0.6765	0.400 ± 0.0007	0.01 ± 0.006	0.046*	0.001 ± 0.004	0.4385	0.420 ± 0.0007	0.009 ± 0.005	0.0285*
FIP	−0.065 ± 0.062	0.86	4.247 ± 0.009	0.204 ± 0.072	0.002*	0.065 ± 0.054	0.1125	4.552 ± 0.009	0.132 ± 0.059	0.013*
BABIP	−0.002 ± 0.003	0.79	0.288 ± 0.0004	−0.002 ± 0.003	0.73	0.002 ± 0.002	0.195	0.296 ± 0.0004	0.002 ± 0.003	0.24

Defensive parameters are shown, where nominally offensive parameters indicate those values allowed by the defensive team. Home and away jet lag show the regression coefficients indicating the effect of jet lag on home- and away-team defensive performance, respectively. Regression coefficients are adjusted for team effects. Parameters are expressed on a per game basis with error indicates SE of the estimated effect. P values are one tailed, derived from the regression analysis testing whether jet lag adversely impacts performance.

^*Metrics where P < 0.05. Average over all 46,535 games.