Table 2.
Summary of metrics by prevalence level [number (%) or median (interquartile range), except for the total number of identifications: mean (standard deviation)]
| Metric | 20% prevalence | 50% prevalence | 80% prevalence |
|---|---|---|---|
| At least one pursuit of polyp | 63/63 (100) | 61/64 (95) | 61/63 (97) |
| Immediate pursuit | 5/63 (8) | 4/64 (6) | 10/63 (16) |
| Time to first pursuit (s)a | 0.45 (0.26–0.65) | 0.52 (0.28–0.82) | 0.52 (0.37–0.95) |
| Total assessment time span (s)a | 2.45 (1.33–5.96) | 1.75 (1.00–3.49) | 2.19 (1.15–5.76) |
| Assessment pursuit time (%) | 24 (14–34) | 21 (13–33) | 18 (12–33) |
| Assessment pursuit rate (s−1) | 0.59 (0.42–0.79) | 0.56 (0.42–0.83) | 0.69 (0.45–0.85) |
| Pursuit rate (s−1) | 2.69 (2.19–3.09) | 2.67 (2.23–3.02) | 2.71 (2.26–3.11) |
| Screen coverage (%) | |||
| Upper | 6 (3–13) | 7 (5–12) | 9 (5–15) |
| Central | 87 (77–92) | 84 (77–90) | 82 (73–89) |
| Lower | 7 (4–12) | 8 (5–13) | 8 (6–13) |
| Total number of identifications | 0.75 (0.82) | 0.93 (0.90) | 0.97 (1.07) |
| Videos with polyps | 1.17 (0.80) | 1.38 (0.90) | 1.43 (1.16) |
| Videos without polyps | 0.34 (0.59) | 0.49 (0.66) | 0.51 (0.73) |
| Any correct identification | 46/65 (71) | 55/64 (86) | 49/65 (75) |
| Any incorrect identification | 39/130 (30) | 48/129 (37) | 51/130 (39) |
| Videos with polyps | 21/65 (32) | 22/64 (34) | 25/65 (38) |
| Videos without polyps | 18/65 (28) | 26/65 (40) | 26/65 (40) |
a
Kaplan–Meier estimate, calculated without allowing for clustering, excluding viewings with immediate pursuit.