Table 2.

The predicted probability of exceeding the median clinical demand (20% mastitis, 20% lameness, 35% Johne’s disease) for the most pessimistic veterinarian, when their prior clinical expectation is combined with synthetic trial data of different sizes using Bayes theorem; the trial data provided a point estimate of a 30% reduction in clinical outcome for mastitis and lameness, and 40% for the Johne’s disease intervention

Disease intervention	Population standard deviation	Size of randomised clinical trial
		20 farms	50 farms	100 farms	200 farms
Mastitis	10%	0.02	0.43	0.97	1.00
	25%	<0.001	0.001	0.01	0.12
Lameness	10%	0.73	0.99	1.00	1.00
	25%	0.11	0.29	0.61	0.92
Johne’s disease	10%	<0.001	0.037	0.41	0.94
	25%	<0.001	<0.001	<0.001	0.003