New IRS Rules Erode Away Tax Cuts
The shift will cost Americans $133.5 billion over a decade, according to Congress’s Joint Committee on Taxation.
In technical terms, the new tax law switched from using the traditional measure of inflation—called CPI-U—to a version known as chained CPI, or consumer-price index.
Many economists view chained CPI as more accurate because it better reflects consumers’ tendency to buy cheaper alternatives as prices increase. The measure typically rises more slowly than CPI-U. For 2019 tax purposes, inflation measured by the rise in chained CPI was 2.06%, compared with 2.42% for CPI-U, according to the Tax Foundation.
https://www.wsj.com/articles/trump-tax-cut-to-be-eroded-next-year-by-inflation-switch-1542302217