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A Bipartisan Case for Chained CPI

Glenn Hubbard and Martin Neil Baily

Over the last few days, politically driven critics have called on the president to abandon his support for changing the way the government indexes provisions in the budget to inflation by switching to “chained CPI.” Looking beyond politics, we’re here to say that these critics’ arguments are wrong on their merits.

As economists from opposite ends of the political spectrum, we would strongly urge the president and leaders in Congress to continue to support moving to chained CPI, which represents the most accurate available measure of inflation and cost-of-living increases. Switching to this more accurate measure of inflation represents the right technical, fiscal and retirement policy—and policymakers should not delay any further in making this improvement.

From a technical sense, the current CPI—or consumer price index—that is used to index many parts of the budget and tax code is widely understood to overstate inflation. This is because it fails to account for so-called “substitution bias,” in which consumers reallocate their purchases depending on the relative prices of similar goods. For example, if the price of apples goes up, consumers will buy more oranges. However, this behavior is not accounted for in standard CPI measurements.

The Bureau of Labor Statistics, which calculates the CPI, is very aware of this shortcoming, which is why it has developed and refined the chained CPI for more than a decade. The nonpartisan Congressional Budget Office states that the chained CPI “provides an unbiased estimate of changes in the cost of living from one month to the next.”

Some argue that using the chained CPI to index Social Security benefits is inappropriate because it does not reflect inflation for retirees, which critics suggest is higher than it is for working-age adults because of the elderly’s higher rate of spending on healthcare. However, the CBO has said that based on the available research, it is unclear whether the cost of living actually grows at a faster rate for the elderly than for younger people, and that the CPI-E  —“E” for “experimental”—which was intended to provide a more accurate measure of inflation for seniors, has several methodological flaws that overstate inflation, including underestimating the rate of improvement in healthcare.

Beyond the technical case for the chained CPI, there is a strong fiscal case. Because current measures currently overstate inflation by about 0.25 percent per year, moving to a more accurate measure would result in real deficit reduction. Measuring inflation more accurately would generate savings from throughout government: about $390 billion in the first decade alone. Roughly one-third of those savings would come from slower growth in Social Security benefits, another third from revenue increases (as certain tax provisions such as the cutoff points of income tax brackets  are indexed to inflation) and the remaining savings from a combination of other spending programs and lower interest payments on the debt. Given the very real need to begin to put our debt on a sustainable path, this would be a small but important contribution. The savings would be gradual, with only a small amount in the near term, thus protecting our fragile recovery from immediate austerity.

Finally, switching to chained CPI is the right retirement policy—or rather, a small piece of it. The Social Security program is on a path to exhaust its trust fund. Current projections indicate that this will occur in 2033, threatening cuts for all beneficiaries, including the very rich and the very poor, the very young and the very old, veterans, disabled workers and others. Improving the way we measure inflation won’t prevent the program’s looming insolvency, but it will eliminate a full fifth of the long-term funding gap.

To the extent that the overpayments under the current formula offset the shortcomings of our current retirement system for the lowest-income and most-elderly beneficiaries, a switch to chained CPI can and should be accompanied by targeted policy changes providing benefit enhancements designed to help the affected populations, rather than providing higher-than-justified inflation adjustments for all beneficiaries.

The federal government should not knowingly continue to measure inflation inaccurately, especially given the costs to the budget and to the Social Security program. Changes that cut Social Security benefits are a tough sell for Democrats, and changes that increase revenue are a tough sell for Republicans. But if they cannot even agree to a technical correction to those areas of the budget, how will they be able to make the hard choices to control our debt and reform our government over the long term?


Glenn Hubbard

Dean & Russell L. Carson Professor of Finance and Economics - Columbia Business School

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