Table 5.

Definition, aim, and calculation of screening indicators

Indicator	Definition	Aim	Calculation
Participation rate	Number of women who have a screening test over all women invited to attend the screening (invited women are those eligible at the date of the invite)	To assess the impact and efficiency of the program in reducing mortality through a direct and proportional effect on the outcome	$\frac{\mathrm{number}\mathrm{of}\mathrm{women}\mathrm{who}\mathrm{have}\mathrm{a}\mathrm{screening}\mathrm{test}}{\mathrm{number}\mathrm{of}\mathrm{women}\mathrm{invited}\mathrm{to}\mathrm{screening}-\mathrm{unreturned}\mathrm{invitations}}$
Recall rate	Number of women recalled for further assessment as a proportion of all women who had a screening examination	To determine, along with other indicators, the specificity of the first level of the program. A further exam is needed to clarify what has been classified as an anomaly at the first level	$\frac{\mathrm{number}\mathrm{of}\mathrm{women}\mathrm{recalled}\mathrm{for}\mathrm{further}\mathrm{assessment}}{\mathrm{number}\mathrm{of}\mathrm{women}\mathrm{who}\mathrm{had}\mathrm{a}\mathrm{screeningexamination}}$
Detection rate	Number of pathologically-proven malignant lesions of the breast detected in a screening round per 1000 women screened in that round	Process indicator that aims at indirectly estimating the efficiency of the screening program	$\frac{\mathrm{number}\mathrm{of}\mathrm{malignat}\mathrm{breast}\mathrm{lesions}\mathrm{detected}\mathrm{in}\mathrm{a}\mathrm{screening}\mathrm{round}}{\mathrm{number}\mathrm{of}\mathrm{women}\mathrm{screened}\mathrm{in}\mathrm{that}\mathrm{round}}$