Measuring the mortality reductions produced by organized cancer screening: a principled approach

In cancer screening trials, or in comparisons involving regions that did/did not introduce population-based screening programs, the mortality reductions are usually summarized by an overall (single-number) mortality reduction. But this overall mortality reduction is an average of minimal reductions in the first years, larger ones after some years, waning ones starting some years after the last screens, smaller ones among those screened a few times and larger ones among those screened several times...