SWS21 data is based on referrals rather than children. On each occasion a child is referred to a Reporter one statistical return is completed and sent to Social Work Services Group. Data from the SWS21 system has a hierarchical structure. This means that a single child may be referred to the system one or any number of times. Any child, therefore, may have multiple records.
Statistics regarding referrals are relatively straightforward to analyse.
Any discussion of the children involved in the system must first aggregate all the individual records of referral for each child. Grouping together the information about individual children requires a number of decisions. Certain things will remain constant, such as the child's identification number, sex, and date of birth. However, even gathering what would be basic statistics in non-hierarchical data sets requires more specific choices. For example, in calculating the average age children were referred to the hearings system, a child may have been referred at a number of ages, and a decision has to be made about which referral age should be the focus of the analysis.