Table 3.

Agreement of invasive and non-invasive cancer histologies over time in participants of the Million Women Study

Year	Number of cases	Percentage agreement	κ value
1996	102a	0.92	0.73
1997	1,093	0.94	0.84
1998	2,018	0.96	0.89
1999	1,572	0.96	0.89
2000	773	0.97	0.91
2001	315b	0.95	0.86

^aLower number of cases in 1996 as this is the first year of recruitment into the Million Women Study.

^bLower number of cases in 2001 as only cases diagnosed up to the end of March 2001 were included in the analysis. Test for trend: X²₁ = 5.2, p = 0.02.