Table A3.

Multivariable Poisson regression models describing the effect of intervention separated by area on the number of OTF‐Wb incidents in the first 2 years since culling began, adjusted for a reduced set of explanatory variables as applied in analysis of the RBCT (Donnelly et al., 2003, 2006). Model 1 describes the effect in the central intervention areas compared with matched central comparison areas, and Model 2 describes the effect in the 2‐km buffer area for the intervention areas compared with buffer areas for matched comparison areas

	IRRa	Robust SE	p value	95% Confidence interval
Model 1—Central areas
Intervention effect in Somerset areab	1.012	0.073	.868	0.879	1.165
Intervention effect in Gloucestershire areab	0.685	0.060	<.001	0.577	0.813
Area = Somerset	1.008	0.082	.926	0.859	1.182
Log transformed herd years at risk in the first 2 years of culling	5.436	1.284	<.001	3.421	8.635
Log transformed OTF‐W incidence rate over all 3 years prior	2.075	0.143	<.001	1.813	2.374
Model 2—Buffer areas
Intervention effect in Somerset buffer areab	0.818	0.103	.111	0.638	1.047
Intervention effect in Gloucestershire buffer areab	0.998	0.140	.987	0.758	1.313
Area = Somerset	1.242	0.209	.199	0.892	1.728
Log transformed herd years at risk in the first 2 years of culling	2.259	0.567	.001	1.381	3.696
Log transformed OTF‐W incidence rate over all 3 years prior	1.588	0.134	<.001	1.346	1.874

Officially Tuberculosis Free status Withdrawn.

^aIncidence rate ratio.

^bIntervention is industry‐led badger culling, as described in the Section 1.