The rules for Sickness Benefit rely on calculating the total income for a household, and comparing that total income to a predetermined threshold.
The total income for the household can vary over time (as can the threshold, shown earlier as a rate table). In order that the system can calculate the total income (later), a record of the father's varying income must be stored on the system.
The case worker captures the history of the father's income since the start of the case, and the system stores the income data using evidence (see Designing Cúram Evidence Solutions).
The father has received pay rises over the lifetime of the income, and so a number of income records are stored within the same evidence succession set. Each evidence record bears the income effective from a particular date (i.e. the date of the pay rise).
While the income evidence is being recorded, each evidence record is "in edit", and so generally is not available to case determination calculations (i.e. would not be converted into rule objects by the active evidence converters). For eligibility and entitlement processing, rule objects represent the "best known truth" about real-world data, and while the evidence is in-edit, it has not yet become "truth", so to speak.
After all the income evidence has been captured and verified, the case worker chooses to activate the evidence, at which point its data becomes part of the system's "best known truth". Later, during case determination, evidence in the "active" state is converted into rule objects so that the evidence data can be used in CER's calculation of the determination result.
Later, during case determination, CER will make a request for the rule object for the father's income. The Active Succession Set Rule Object Converter will retrieve all the active evidence versions for the father's income (which form a single "succession set" of evidence) and create a single rule object representing the father's income changing over time. The rule object created has:
At this point we have all the data required in order to calculate the case's eligibility and entitlement (but no such calculation has yet occurred for this case).