Table 1. Inter-observer variability at single reading by eight radiologists (A–H): mammography screening outcome at 2-year follow-up.

	A	B	C	D	E	F	G	H	Total
Total readings, no. (%)	23 872 (11.3)	28 244 (13.3)	26 874 (12.7)	26 754 (12.6)	26 101 (12.3)	28 317 (13.3)	25 541 (12.0)	26 483 (12.5)	212 186
1st reading, no. (%)	10 178 (42.6)	11 614 (41.1)	12 708 (47.3)	11 403 (42.6)	14 493 (55.5)	16 467 (58.2)	15 696 (61.5)	13 534 (51.1)	106 093
2nd reading, no. (%)	13 694 (57.4)	16 630 (58.9)	14 166 (52.7)	15 351 (57.4)	11 608 (44.5)	11 850 (41.8)	9845 (38.5)	12 949 (48.9)	106 093
No. of referrals (%)	96 (0.9)	147 (1.3)	141 (1.1)	158 (1.4)	224 (1.5)	188 (1.1)	200 (1.3)	161 (1.2)	1315 (1.2)
Screen-detected cancers, no. (%)	35	57	64	57	66	80	76	57	492
CDR, per 1000 women (95% CI)	3.44 (2.30–4.58)	4.91 (3.64–6.18)	5.04 (3.81–6.27)	5.00 (3.70–6.29)	4.55 (3.46–5.65)	4.86 (3.80–5.92)	4.84 (3.76–5.93)	4.21 (3.12–5.30)	4.64 (4.23–5.05)
Non-screen-detected cancers, no.	33	32	36	19	29	41	41	47	278
Cancer prevalence, per 1000 women (95% CI)	6.68 (6.20–7.17)	7.66 (7.18–8.15)	7.87 (7.40–8.34)	6.66 (6.12–7.12)	6.55 (6.15–6.96)	7.35 (6.15–6.96)	7.45 (7.04–7.87)	7.68 (7.24–8.13)	7.26 (7.10–7.41)
Sensitivity, % (95% CI)	51.5 (39.6–63.3)	64.0 (54.1–74.0)	64.0 (54.6–73.4)	75.0 (65.3–84.7)	69.5 (60.2–78.7)	66.1 (57.7–74.5)	65.0 (56.3–73.6)	54.8 (45.2–64.4)	63.9 (60.5–67.3)
Specificity, % (95% CI)	99.4 (99.2–99.5)	99.2 (99.1–99.4)	99.4 (99.3–99.5)	99.1 (98.9–99.3)	98.9 (98.7–99.1)	99.3 (99.2–99.5)	99.2 (99.1–99.3)	99.2 (99.1–99.4)	99.2 (99.1–99.3)
PPV, % (95% CI)	36.5 (26.8–46.1)	3 8.8 (30.9–46.7)	45.4 (37.2–53.6)	36.1 (28.6–43.6)	29.5 (23.5–35.4)	42.6 (35.5–49.6)	38.0 (31.3–44.7)	35.4 (28.0–42.8)	37.4 (34.8–40.0)

CDR=cancer detection rate; CI=confidence interval; PPV=positive predictive value of referral.