Statistical data linkage refers to the bringing together of data from different sources to gain a greater understanding of a situation or individual from the combined (or linked) dataset. This facilitates a better understanding of the patterns of service use by groups of clients for research, statistical or policy analysis, planning and evaluation purposes.

Its form is: XXXXXDDMMYYYYX

The sequence in which the linkage key is completed is as follows:

• Family name (the first 3 Xs)
• Given name (the 4th and 5th X)
• Date of birth by day (DD), month (MM) and 4-digit year (YYYY)
• Sex (last X).

XXX 2nd, 3rd and 5th letters of the family name.

In the first three spaces the agency should record the 2nd, 3rd and 5th letters of the person’s family name.

For example: If the person’s family name is Smith the reported value should be MIH. If the person's family name is Jones the reported value should be ONS.

Regardless of the length of a person’s name, the reported value should always be three characters long. If the legal family name is not long enough to supply the requested letters (i.e. a legal family name of less than five letters) then agencies should substitute the number ‘2’ to reflect the missing letters. The placement of a number ‘2’ should always correspond to the same space that the missing letter would have within the 3-digit field. A number (rather than a letter) is used for such a substitution in order to clearly indicate that an appropriate corresponding letter from the person’s name is not available.

Cases where the family name has less than 5 letters:

If a person’s family name is Farr, then value reported would be AR2 because the 2 is substituting for a missing 5th letter of the family name. Similarly, if the person’s family name was Hua, then the value reported would be UA2 because the 2 is substituting for the missing 5th letter of the family name.

If a person’s family name is missing altogether the agency should record the number 999 for all three spaces associated with the family name, (not the number 2). In some cultures it is traditional to state the family name first. To overcome discrepancies in recording/reporting that may arise as a result of this practice, agencies should always ask the person to specify their legal first given name and their legal family name separately. These should then be recorded as first given name and family name as appropriate, regardless of the order in which they may be traditionally given.

If the person’s family name includes non-alphabetic characters—for example hyphens (as in Lee-Archer), apostrophes (as in O’Mara) or blank spaces (as in De Vries)—these non-alphabetic characters should be ignored when counting the position of each character.

XX 2nd and 3rd letters of the given name

In the fourth and fifth spaces the agency should record the 2nd and 3rd letters of the person’s given name.

For example: If the person’s given name is Elizabeth the reported value should be LI. If the person's given name is Robert the reported value should be OB.

If the person’s given name includes non-alphabetic characters—for example hyphens (as in Jo-Anne) or apostrophes (as in D'Arcy), these non-alphabetic characters should be ignored when counting the position of each character.

Regardless of the length of a person’s given name, the reported value should always be two characters long. If the given name of the person is not long enough to supply the requested letters (i.e. a name of less than three letters) then agencies should substitute the number ‘2’ to reflect the missing letters. The placement of a number ‘2’ should always correspond to the same space that the missing letter would have within the 2-digit field. A number (rather than a letter) is used for such substitutions in order to clearly indicate that an appropriate corresponding letter from the person’s name is not available.

For example: If the person’s legal name was Jo then the value reported would be O2 because the 2 is substituting for the missing 3rd letter of the given name.

If the person’s given name is missing altogether the agency should record 99 for the two spaces associated with the given name. In some cultures it is traditional to state the family name first. To overcome discrepancies in recording/reporting that may arise as a result of this practice, agencies should always ask the person to specify their given name and their family name separately. These should then be recorded as first given name and family name as appropriate, regardless of the order in which they may be traditionally given.

Date of Birth

In the sixth to thirteenth spaces the agency should record the day, month and year a person was born as follows:

• DD represents the day in the month a person was born
• MM represents the month in the year a person was born
• YYYY represents the year a person was born.

If date of birth is not known or cannot be obtained, provision should be made to collect or estimate age. Collected or estimated age would usually be in years for adults and to the nearest three months (or less) for children aged under 2. Additionally, an estimated date flag or a date accuracy indicator should be reported in conjunction with all estimated dates of birth.

For data collections concerned with children's services, it is suggested that the estimated date of birth of children aged under 2 should be reported to the nearest 3 month period, i.e. 0101, 0104, 0107, 0110 of the estimated year of birth. For example, a child who is thought to be aged 18 months in October of one year would have his/her estimated date of birth reported as 0104 of the previous year. Again, an estimated date flag or date accuracy indicator should be reported in conjunction with all estimated dates of birth.

Sex

In the fourteenth space the agency should record the sex of the person.  The term 'sex' refers to a person's biological characteristics. Codes 1 or M are used to record 'Male'. Codes 2 or F are used to record 'Female'. Codes 3 or X are used to record 'Other'. Code 9 is used to record 'Not stated/inadequately described'.

Data that has been produced by linkage for statistical and research purposes should not be used subsequently for client management purposes.

This data cluster contains a set of specific data elements to be reported on in a predetermined combination.