A note on a 'close pairs' test for space clustering.

Lloyd and Roberts (1973) have recently proposed in this journal a test for spatial clustering. For the 57 cases of congenital limb defects diagnosed in singleton births in Cardiff over the three-year period 1964-67, they calculated the total number of pairs, Z*, of cases whose places of residence at birth were less than a certain critical distance, d, apart… CONTINUE READING