Virtually all Catholic dioceses have an assessment, which is generally used to fund diocesan operations and services to parishes. Usually based on a percentage of the annual revenue of a parish, the assessment is sometimes adjusted to reflect area incomes, parish operating costs, and other factors. The Detroit Archdiocese assessment is based on parish operating revenue, including offertory collections (except Christmas), net fundraising income, net rental income, bequests and donations, and other miscellaneous operating income of the parish.
The 7 percent assessment in the Detroit Archdiocese is lower than most dioceses of comparable size in the United States, some of which have rates as high as 17 percent. The relatively low parish assessment rate in the Archdiocese of Detroit is due in part to the consistent success of the CSA, which is the largest annual campaign of its kind in the nation. The Archdiocese of Detroit assessment was raised 1 percentage point from 6 to 7 percent, effective July 1, 2010, based on parish financial reports submitted for fiscal year 2009 – 2010. Prior to this increase the assessment had been at 6 percent for more than 35 years.