Table 1. The Malmö mammographic screening trial assessed as a randomised trial (Janzon and Andersson, 1991).

	Invited (n=21 088)	Controls (n=21 195)
Proportion	50%	50%
Breast cancer deaths	63 (31 were non- participants)	66
Mortality rate	0.299%	0.311%
Relative risk	0.96 (95% CI 0.68–1.35)