0 a set of letters and numbers added to the address on a letter to make delivery easier; zip code American -- postnummer
The use of postcode district to geocode the data safeguarded patient confidentiality.
In total, 144 controls were recruited in postcode areas where 16 of the 19 definite and 17 of the 31 probable cases resided.
The smallest postcode district is 0.69 km2, whereas the largest is 3400 km2, and they have a median size of 69.5 km2.
The postcode of each patient was also linked to an enumeration district using a lookup table.
This includes socio-demographic information, postcode, clinical details, and identification of each patient's problems preceding the act of selfharm.
For small sites, attempts to use local postcode data and population density proved complex.
Cattle may be grazed or indeed housed some distance from the identified farm of origin, possibly in neighbouring postcode districts.
Linkage was based upon the first letter of the family (maiden) name, gender, date of birth, residence, and postcode of the general practitioner (identifiers).
