Actually, Social Security's COLA is calculated using the full CPI, not the core. It is based on the average of the CPI in the months July, August and September for the following January's CPI. It got screwed up in 2009 when there was a huge jump in fuel and food prices in the summer of 2008 (first time gasoline hit $4), so the 2009 COLA was over 6%. The gas bubble burst very soon after ($1.41 by Christmas 2008), which meant that there was a big drop in CPI in 3rd quarter 2009 with a rise but not up to the peak in 2010 3Q, so the COLA was 0% in 2009 and 2010. Essentially SS recipients got three years of COLA in January 2009 because of that summer price spike.
http://www.ssa.gov/oact/cola/latestCOLA.html
http://www.ssa.gov/oact/STATS/cpiw.html
Is the CPI-W (for Urban Wage Earners and Clerical Workers) an accurate measure of real price increases? Like most it is probably aimed low to benefit the government with lower COLAs and inflation adjusted bond yields, but it is the one the COLA is based on by law.
Thanks again from the information.
... so the COLA was 0% in 2009 and 2010.
That must be what is affecting my thinking because I haven't seen any movement in quite a long time despite increasing costs across the board.