FINDING THE VALUE OF N

To achieve the same number of false segment-matches for both randoms and relatives, values of N between 7 and 9 clearly work best. But N=9 produces too many false relative matches given that some of the 7cM (yellow) matches are false as well. N=7 gives the closest unadjusted match but does not allow enough room for the false yellow matches. N=8 appears to be the conservative choice.

That relatives and randoms have the same number of false segment-matches is a corollary of the obvious assumption that the 187 extra relative segment-matches are all real.