Relationships among the Otmoor villages and surrounding communities as inferred from surnames contained in the current register of electors.

The interrelationships of 17 villages and a town near Otmoor have been investigated by means of the coefficients of relationships by isonymy: Ri = sigma(Si1Si2)/2N1N2 in which Si1 and Si2 are the respective frequencies of the ith surname in communities 1 and 2 and N1 and N2 are the respective sample sizes. The coefficients calculated from all adult males listed in the current registers electros range from 0 to over 0.008. The coefficient of relationship within the town and between the town and villages average 0.0005. Those between villages average 0.0007. The correlation between the coefficient of relationship by isonymy wth the frequency of marriages between parishes is +0.75 but this high correlation rests largely on a few very closely related pairs of parishes and largely on the contribution to Ri of relatively rare surnames. The method can easily be applied to wide surveys, and even to historic data, to explore the development of intercommunity relationships in the period since surnames became general.