Certainty for Older Living Americans Act of 2021 or the COLA Act of 2021 This bill sets out an alternative method to calculate cost-of-living adjustments for Social Security benefits. The current method is based on the annual change in the Consumer Price Index for Urban Wage Earners and Clerical Workers, which results in no or small increases to benefits following a year with deflation or low inflation. The alternative method established by this bill is based on a 10-year average of cost-of-living adjustments. The Social Security Administration must use whichever method results in the larger increase for a given year. In addition, the Department of Labor and the Department of Commerce must establish a working group to make recommendations on incorporating specified economic data when producing relevant consumer price indexes.