HUD has released the operating cost adjustment factors (OCAFs) for project based assistance contracts for eligible multifamily housing projects having an anniversary date on or after February 11, 2012. OCAFs are annual factors used to adjust renewed Section 8 rents. OCAFs are calculated based on average cost changes for wages, employee benefits, property taxes, insurance, supplies and equipment, fuel oil, electricity, natural gas, and water/sewer/trash. 2012 OCAFs, effective starting in February 2012, are available here.