Assessment is a portion of income provided by each parish for the operation and services of the Synod. Assessment income comprises approximately one third of Synod revenue. The rate of parish income to be contributed to the Synod is determined at the Annual session of Synod as part of the finance and budget motions.
As of 2017, it is set at 16% of all parish income, which is declared to Diocesan Office annual in the Parish Annual Assessment Return. Diocesan Council specifies categories of expenses as deductions against assessable income so as to incentivise certain activities. The setting, apportionment, and collection of Assessment is governed by the Assessment Ordinance.