Your Social Security payments are not guaranteed to have a cost-of-living adjustment each year. To determine if a COLA will apply, the Social Security Administration, in the 3rd quarter of the year, looks at what percentage increase, an economic indicator known as the CPI-W* has had since the 3rd quarter of the previous year. Whatever percentage that indicator has increased will be applied to Social Security benefits for the next calendar year.
If there is no increase, there can be no COLA. If there is a percentage decrease in that indicator there is no subsequent reduction in Social Security benefits.
Over the last 10 years, there have been eight cost of living adjustments.