The NDNAD does not hold any information on the place of residence of a person whose DNA is sampled. This figure therefore includes residents of areas other than Northern Ireland who were sampled by the PSNI, and excludes residents of Northern Ireland who were sampled by other police forces.
The number of profiles held on the NDNAD is not the same as the number of individuals. As it is possible for a profile to be loaded onto the NDNAD on more than one occasion, some profiles held on the NDNAD are replicates. This can occur if, for example, a person provided different names, or different versions of their name, when arrested on different occasions. At present, the average replication rate on the whole NDNAD is estimated to be 13.3 per cent. However, this figure may vary between police forces.