The Social Security Administration bases its inflation adjustment for Social Security checks on the average inflation rate in this year's third quarter compared with the previous year's third quarter.

That means the inflation rates nationwide for July, August and September are what matter. Last year, inflation was running very low in August, at a 1.8 percent rate, and not much higher in July, at 2.3 percent and at 2.8 percent in September.

This year, inflation is not that low. The most recent reading we have was a 4.5 percent annual rate in May.

It's different from the CPI-U, the Consumer Price Index for all urban consumers, which is the rate quoted most often. That was 4.2 percent in May. The Social Security adjustment is pegged by law to the CPI-W, which measures costs for households that have hourly wage earners or clerical workers.

The CPI-W is often used in labor negotiations. It is based on a survey of 32 percent of the total U.S. population, according to the U.S. Bureau of Labor Statistics. The CPI-U is a larger survey based on 87 percent of the U.S. population.

Social Security Inflation at Sun-Sentinel.com