U.S. Citizenship and Immigration Services: Backlog Elimination Plan: Fiscal Year 2006, 4th Quarter Update [open pdf - 2MB]
"The USCIS quarterly report is designed to provide Congress with an update on the progress USCIS has made in its effort to eliminate the backlog of pending applications for immigration benefits by the end of FY 2006. This report will cover the progress made during the fourth quarter of FY 2005. Changes in the number of pending cases is itself significant when looking at performance. For the 4th quarter, pending fell by 594,560. But the pending level can be affected by changes in demand as well as production, and is not the best indicator of processing time. Current technology systems employed by USCIS District Offices and Service Centers are unable to produce reliable aging reports from which average wait times or processing times can be calculated. That said, USCIS believes that the 'Cycle Time' measurement, pending expressed in months of receipts, in conjunction with the first-in-first-out adjudication policy comes close to approximating average processing time. USCIS continues to define 'Backlog,' generally, as the number of pending cases that exceed acceptable or target pending levels for each case type. Acceptable pending levels are determined for each distinct case type by totaling the number of cases received during the target cycle-time period (usually six months). Backlogs are calculated for each case type, then totaled to determine the aggregate backlog. This ensures that backlogs in a product are not obscured by faster production of other products."
U.S. Citizenship and Immigration Services: http://www.uscis.gov/