Table 4. Maximum likelihood admixture estimates for the most stringent and the least stringent criteria used to define local and non-local surnames.

‘Admixed' population	Parental populations	Local (L) or non-local (N)	Proportion East	−95% CI	+95% CI
LQ>120, distance<83 kma
CN	West vs East	L	0.945	0.895	0.995
CN	West vs East	N	0.630	0.591	0.669
OR	West vs East	L	0.550	0.488	0.614
OR	West vs East	N	0.695	0.630	0.760
LQ>19, distance<120 kmb
CN	West vs East	L	0.900	0.829	0.971
CN	West vs East	N	0.525	0.482	0.568
OR	West vs East	L	0.360	0.265	0.455
OR	West vs East	N	0.815	0.761	0.869
‘Admixed' population	Parental populations	Local (L) or non-local (N)	%Norse	−95% CI	+95% CI
LQ>120, distance<83 kma
OR	Norse vs West	L	0.375	0.331	0.419
OR	Norse vs West	N	0.405	0.357	0.453
LQ>19, distance<120 kmb
OR	Norse vs West	L	0.315	0.266	0.364
OR	Norse vs West	N	0.420	0.375	0.465

The contributions of the putative ancestral populations (East, West and Norse) to the putative admixed population (Central (CN) or Orkney (OR)) were estimated for either the local surnames (L) alone or only the non-local (N) surnames. For the Orkney anaylsis, all Orcadian samples were compared with either local or non-local stratified PoBI samples.

^aMost stringent criteria

^bLeast stringent criteria