According to the BLS, its most recent re-classification of education in the Consumer Expenditure (CE) survey better reflects income and spending patterns in the US. The BLS reports this in Beyond the Numbers: Prices & Spending, vol. 3, no. 1 (U.S. Bureau of Labor Statistics, January 2014.
Starting with the release of calendar year 2012 CE data, classification of household expenditures by the education of the reference person was changed. In the latest release, and into the future, education will be replaced by classification by the highest level of education attained by any consumer unit (CU) member. So for example, if the Husband is the reference person and has a Bachelor’s degree and the wife has a Post-graduate degree, the household’s education in the post 2012 data will be classified as Post-Graduate instead of Bachelors/College Graduate.
Ann Foster, the author of article, states that the rationale for the change was that the highest level of education attained by any household member more accurately reflects income and spending patterns than does the education level of the reference person only.
Ann C. Foster, “New education classification better reflects income and spending patterns in the Consumer Expenditure Survey ,” Beyond the Numbers: Prices & Spending, vol. 3, no. 1 (U.S. Bureau of Labor Statistics, January 2014), http://www.bls.gov/opub/btn/volume-3/education-classification-and-income-and-spending-patterns.htm