How important is the COLA? From 2001 to 2011, household incomes in the U.S. dropped for every age group except one: those 65 and older.
The median income for all U.S. households fell by 6.6 percent, when inflation was taken into account, according to census data. But the median income for households headed by someone 65 or older rose by 13 percent.
"That's all because of Social Security," Certner said. "Social Security has the COLA and that's what's keeping seniors above water, as opposed to everybody else who's struggling in this economy."
Seniors still, on average, have lower incomes than younger adults. Most older Americans rely on Social Security for a majority of their income, according to the Social Security Administration.
"It's useful to bear in mind that no other group in the economy gets an automatic cost-of-living increase in their income," said David Blau, an economist at The Ohio State University. "Seniors are the only group."
Still, many feel like the COLA doesn't cover their rising costs.
"You have utilities go up, your food costs go up. Think about how much groceries have gone up," said Janice Durflinger, a 76-year-old widow in Lincoln, Neb. "I would love to know how they figure that."
The COLA is based on the Consumer Price Index for Urban Wage Earners and Clerical Workers, or CPI-W, a broad measure of consumer prices generated by the Bureau of Labor Statistics. It measures price changes for food, housing, clothing, transportation, energy, medical care, recreation and education.
In the past year, food prices have risen 2 percent while home energy prices have dropped 3.8 percent, according to the CPI-W. Housing costs have climbed by 1.4 percent and gasoline prices have increased by 1.8 percent.