"They gripe about it a lot," said Kopalle, who studies consumer pricing. As seniors pay more for health care and other services that don't factor prominently into the CPI, the apparent disconnect between their cost of living and their benefits creates a "conundrum" for them, he said.
The solution to the problem, some say, is to establish a pricing index that focuses specifically on the elderly and their spending habits.
A bill introduced in Congress earlier this year aims to do just that: Under the Consumer Price Index for Elderly Consumers Act of 2009, proposed before the House in May 2009, spending by Americans 62 or older would be monitored and used to calculate Social Security and Medicare benefits.
"We must provide the basic benefits that our seniors can count on, regardless of the ups and downs of the economy," Rep. Charles A. Gonzalez, D-Texas, said in a written statement earlier this summer. "My legislative proposal is a rational approach to a very real problem."
But if the bill is passed -- never a sure bet, especially at a time when health care reform itself seems to overshadow everything else -- it won't be a quick fix, experts say.
The U.S. Bureau of Labor Statistics has actually had an elderly-spending index for years, but it's an experimental one. Making the index viable for use on things like Social Security benefits, said BLS economist Sanjeev Katz, would require overcoming some serious statistical hurdles.
The new index wouldn't be ready in time to force an increase in Social Security benefits in 2010, said AARP's Firvida.
"It's not ready for prime time," she said. "You can't just ramp this up and replace the CPI-W."
The lack of a benefit increase, Firvida added, "is not the kind of contingency I think that people planned for."
ABC News' Nathalie Tadena contributed to this report.