Stop Misusing Higher Education-Specific Price Indices

This report examines two commonly used higher education price indices, the Higher Education Price Index (HEPI) and the Higher Education Cost Adjustment (HECA), finding that these indices are almost always misused and suffer from significant biases. Both the HEPI and HECA are often used to discount tuition levels; however, both indices are inappropriate for such a use. The whole point of using a price index in this instance is to put otherwise incomparable values into the same context, something that an industry-specific price index does not allow. These indices also suffer more than most price indices from several sources of bias, including productivity bias, quality bias, substitution bias, and (in the case of the HEPI) from a self-referential bias.

By Andrew Gillen and Jonathan Robe | March 2011

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Over the past half century, college costs (measured either by direct institutional expenditures or by tuition charges) have soared. To understand these trends, it is usually important to isolate the increases that are due to inflation in general as opposed to inflation in higher education. Some have argued that only higher education specific price indices—not broad based price indices—should be used for examining the rise in college costs over time because they are specially designed to accurately reflect the spending patterns of colleges and universities. While higher education specific price indices are useful for some purposes, such as internal budgeting, they are often misused. For instance, these indices are commonly used to adjust tuition levels over time, a task for which an industry specific price index is inappropriate.

A wise man once noted that “the most common misuse of price indexes is to apply them to data or situations they were not designed to cover.”[1] The author of that statement was none other than Dr. D. Kent Halstead, father of the Higher Education Price Index, which he created because he viewed the use of the Consumer Price Index as inappropriate in some situations. In a cruel twist of fate, his creation (and its offspring), are now the price indices that are routinely misused.

These higher education specific indices are also subject to quality, productivity, and substitution biases, and in one instance, are self-referential. Although these indices do serve a limited function, most publicly available examples of their use are inappropriate.

What is the Purpose of a Price Index?

A price index makes possible valid comparisons of the price of goods and services across time. Comparing, for example, the cost of a newspaper in the 1950s to the cost of a newspaper today is an “apples to oranges” comparison because the purchasing power of a dollar today is significantly different than it was in 1950. Adjusting the historical figures for inflation through the use of a price index allows for an “apples to apples” comparison. Essentially, the price index holds the purchasing power of a dollar constant over time to reveal any changes in the “real” cost of goods or services.

Perhaps the best known and most widely used price index is the Consumer Price Index (CPI), calculated and published by the U.S. Bureau of Labor Statistics (BLS). The CPI measures the change in the overall price level over time for a group (called a basket) of consumer goods and services (such as food, housing, clothing, education, and medical services).[2]

Limits on the Uses of Price Indices

There are limits to the appropriate use of any given price index. For example, in calculating the change over time in prices paid by producers (that is, a change in the cost of inputs) it would be inappropriate to use the CPI since it focuses on goods and services that consumers buy. It would probably be preferable to use the Producer Price Index (PPI), also published by the BLS. While the PPI may be appropriate in this case, it is in turn of limited usefulness  in others since it is not a measure of general inflation. To compare the cost of the output (as opposed to the inputs) over time, or the cost of inputs compared to other items, a commonly used measure of general inflation such as the CPI will need to be used.[3]


As noted above, it may be possible to develop a more useful price index than the CPI for the task at hand. Within higher education, two such alternative price indices have been developed, the Higher Education Price Index (HEPI) and the Higher Education Cost Adjustment (HECA). Of these two, HEPI was developed first. Although there are important differences between the two indices and the methodologies employed to compute them, the underlying rationale for both is that a price index based on the spending patterns of colleges and universities is more appropriate than an index based on a broader range of goods and services purchased by consumers.

The Commonfund Institute, which maintains the HEPI, argues that because the HEPI accounts for the difference in purchasing patterns between the higher education industry and consumers at large, it provides a “more accurate indicator of cost changes for colleges and universities.”[4] A similar case is made for the HECA as well.[5] This is a valid point, and HEPI and HECA can be useful indices in certain circumstances. However, while it is true that the goods and services purchased by institutions of higher education  are not the same as those purchased by consumers, this fact does not imply that indices which account for these differences are necessarily superior to the CPI in measuring price changes in higher education for all purposes. As we document later on, there are legitimate uses of both HEPI and HECA, but there are illegitimate uses as well.

Download the entire report (pdf, 21 pp.)


[1] D. Kent Halstead, Higher Education Prices and Price Indexes, Washington DC: U.S. Office of Education, 1975.

[2] For a complete list of all expenditure categories included in the calculation of the CPI, see U.S. Bureau of Labor Statistics, “CPI Detailed Report: Data for September 2010,” Table 1. Washington DC: Bureau of Labor Statistics, 2010. The current and archived versions of this report are available at the BLS website: Accessed October 20, 2010.

[3] Another general measure of inflation that is gaining in acceptance is the Personal Consumption Expenditures (PCE), published by the Bureau of Economic Analysis.

[4] Commonfund Institute, “2010 HEPI Update,” Commonfund, 2010, p. 2.

[5] State Higher Education Executives Organization, “State Higher Education Finance FY 2009: Technical Paper A,” Washington DC: State Higher Education Executives Organization, 2010.

Andrew Gillen is the Research Director at the Center for College Affordability and Productivity. He received his PhD in Economics from Florida State University.

Jonathan Robe is a Research Associate at the Center for College Affordability and Productivity.