The numbers in pink show our estimates of the numbers of cases which were not notified by NHSCR or any other source. Did you get the same?
What assumption is made by this method of estimating the number of unknown cases missed by all sources?

The assumption that ascertainment by NHSCR and other sources is independent.

Do you think this assumption is valid?

No, because several of the other registries inform NHSCR of cases.

Do you think this results in an over-estimate or an under-estimate of the number of unknown cases?