Table 1

Response rate for the Million Women Study*

Estimated number of women who were sent a questionnaire
227 000

when they were invited for screening






Estimated number who were screened (75% of those invited [1])
170 000





Number of women who returned a questionnaire
121 129
(53% of those invited and 71% of those screened)




Number of women who returned a questionnaire with full
113 104
(50% of those invited, 66% of those screened and




identification details and signed permission for follow-up

93% of those returning a questionnaire)




Number of women who returned a questionnaire without full
8025
(3.5% of those invited, 4.7% of those screened and




identification details and/or signed permission for follow-up

6.6% of those returning a questionnaire)





*For the first printing of the Million Women Study questionnaire.

The Million Women Study Collaborative Group Breast Cancer Res 1999 1:73   doi:10.1186/bcr16