Table A4.

Multivariable Poisson regression models describing the effect of intervention (badger culling) stratified by area on the number of OTF‐Wa incidents in the year prior to the culls, adjusted for explanatory variables. 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

	IRRb	Robust SE	p value	95% Confidence interval
Model 1—Central areas
Intervention effect in Somerset areac	1.049	0.078	.521	0.907	1.212
Intervention effect in Gloucestershire areac	0.588	0.100	.002	0.422	0.821
Area = Somerset	1.002	0.139	.986	0.764	1.315
Log transformed herd years at risk in year prior to culls	1.642	0.337	.016	1.098	2.454
Log transformed OTF‐W incidence rate over 2 years prior	1.917	0.258	<.001	1.472	2.496
Log transformed median herd size	1.482	0.798	.465	0.516	4.260
Proportion of herds that are dairy	1.004	0.003	.229	0.997	1.011
Distance to intervention (km)	0.999	0.001	.635	0.997	1.002
Estimated badger sett density per 100 km2	1.000	0.005	.924	0.991	1.010
Proportion of land involved in proactive culling in the RBCT	0.948	0.035	.145	0.882	1.019
Log transformed number of badgers culled historically	0.990	0.010	.316	0.971	1.010
Model 2—Buffer areas
Intervention effect in Somerset areac	1.036	0.129	.777	0.811	1.322
Intervention effect in Gloucestershire areac	1.097	0.212	.632	0.751	1.603
Area = Somerset	0.934	0.083	.444	0.785	1.112
Log transformed herd years at risk in year prior to culls	1.989	0.211	<.001	1.615	2.449
Log transformed OTF‐W incidence rate over 2 years prior	1.702	0.185	<.001	1.376	2.105
Log transformed median herd size	1.626	0.318	.013	1.108	2.386
Proportion of herds that are dairy	1.000	0.005	.969	0.991	1.010
Distance to intervention (km)	1.003	0.002	.149	0.999	1.006
Estimated badger sett density per 100 km2	0.271	0.138	.011	0.100	0.737
Proportion of land involved in proactive culling in the RBCT	1.007	0.005	.185	0.997	1.018
Length of motorway in the area	1.005	0.006	.422	0.993	1.017

^aOfficially Tuberculosis Free status Withdrawn.

^bIncidence rate ratio.

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