Experimental Design Details
To experimentally assign women to the different treatment groups, we make use of the random allocation of subjects in the Messina screening program based on the date of having the mammography. Every year, eligible women are invited to have a mammography at the health care center serving the health district of residence. There are five health care centers in the Province, serving eight health districts; annually these health care centers offer sufficient mammography appointment slots for the target population. Slots are distributed throughout the year and the LHA invites eligible women to have a mammography on an available date. Importantly for our purposes, patients are randomly assigned to screening dates by the LHA computer system. Our manipulations affected women invited for screening during the 7th to 11th week of 2017, the dates being from February 13 to March 19. We sent a different invitation letter to women for each week.