Good News in the CPI

The Big Picture: "There are several different ways to calculate annual consumer inflation.
The two most common ways BLS officials do this is to compare a) December to December, calendar year data; b) annual average CPI for 2008 versus average for 2007.
Most years, the variations between these approaches is quite minor. However, given the volatility we have seen in inflation data — most especially food, energy and commodity prices — this year, the two approaches produce very different results:
A mathematical oddity in Friday’s consumer price index means you can claim with some statistical backing that inflation last year was either 0.1% or 3.8%."
Good News in the CPI