Table 2. Probabilities of Human and Ruminant Fecal Contamination around Lake Rådasjön Based on Expert Judgments (Prior) and Expert Judgments Combined with BacH and BacR Assay Performance (Posterior).

	prior		posterior
site	P(H)a	P(R)a	P(H|T)b	P(H|T′)b	P(R|T)c	P(R|T′)c
	0.39d	0.06	0.57	0.13	0.26	0.01
1	(0.17–0.65)e	(0.01–0.20)	(0.28–0.82)	(0.02–0.42)	(0.04–0.65)	(0.00–0.06)
	0.65	0.24	0.80	0.32	0.64	0.05
3	(0.45–0.81)	(0.11–0.43)	(0.60–0.91)	(0.06–0.65)	(0.34–0.87)	(0.01–0.18)
	0.26	0.26	0.43	0.08	0.66	0.05
4	(0.14–0.40)	(0.11–0.48)	(0.23–0.63)	(0.01–0.24)	(0.34–0.89)	(0.01–0.20)
	0.60	0.15	0.79	0.27	0.49	0–03
6	(0.36–0.81)	(0.05–0.32)	(0.51–0.91)	(0.05–0.64)	(0.19–0.80)	(0.00–0.12)
	0.79	0.15	0.89	0.50	0.49	0.03
7	(0.61–0.92)	(0.09–0.24)	(0.74–0.96)	(0.11–0.81)	(0.27–0.76)	(0.00–0.09)
	0.39	0.20	0.57	0.14	0.58	0.04
10	(0.22–0.57)	(0.10–0.34)	(0.34–0.77)	(0.02–0.38)	(0.31–0.83)	(0.01–0.13)
	0.06	0.16	0.12	0.01	0.51	0.03
15	(0.01–0.17)	(0.06–0.33)	(0.02–0.33)	(0.00–0.08)	(0.21–0.81)	(0.00–0.12)
	0.09	0.78	0.18	0.02	0.95	0.37
17	(0.04–0.18)	(0.39–0.98)	(0.07–0.36)	(0.00–0.09)	(0.74–1.00)	(0.04–0.90)
	0.62	0.26	0.78	0.29	0.66	0.05
18	(0.25–0.91)	(0.09–0.52)	(0.40–0.96)	(0.04–0.76)	(0.30–0.90)	(0.01–0.22)
	0.38	0.12	0.57	0.13	0.44	0.02
19	(0.19–0.62)	(0.04–0.28)	(0.30–0.80)	(0.02–0.40)	(0.15–0.76)	(0.00–0.09)

^aPrior probabilities of a human P(H) and ruminant P(R) fecal contamination at each site determined from expert judgments.

^bP(H|T) is the probability for a true human contamination, given a positive result in the BacH assay, and P(H|T′) is the probability given a negative result in the BacH assay.

^cP(R|T) is the probability for a true ruminant contamination, given a positive result in the BacR assay, and P(R|T′) is the probability given a negative result in the BacR assay.

^dMedian values.

^eRange indicated by 5- and 95-percentile values.