Question: what is the difference between cpi (consumer price index) and chain cpi?
Answer: In general, because the chained CPI controls for the fact that people substitute away from items with large price increases, it tends to be a bit lower than the primary CPI. Since 2000, the primary CPI has risen by 45.7 percent and the chained CPI by only 39.7 percent, a difference of 6 percentage points.