In another strand of research on knowledge capital next to the international analyses, we study whether the substantial differences in GDP per capita that exist across US states are related to the education of the population. We develop detailed measures of the knowledge capital of each state's population that do not just reflect the quantity of education, but also its quality as measured by test scores. We find that differences in knowledge capital account for 20-30 percent of the state variation in per-capita GDP. These results also allow us to quantify the substantial economic gains that could be reaped from improvements of the schools in the US states.
Knowledge Capital and Aggregate Income Differences: Development Accounting for US States (with E.A. Hanushek and J. Ruhose). American Economic Journal: Macroeconomics 9 (4): 184-224, 2017
Economic Gains from Educational Reform by US States (with E.A. Hanushek and J. Ruhose). Journal of Human Capital 11 (4): 447-486, 2017
It Pays to Improve School Quality (with Eric A. Hanushek and Jens Ruhose). Education Next 16 (3): 52-60, 2016
Endangering Prosperity: A Global View of the American School (with E.A. Hanushek and P.E. Peterson). Washington, DC: Brookings Institution Press, 2013
With a foreword by Lawrence H. Summers, former US Secretary of the Treasury and President of Harvard University
Rechnen macht reich (with E.A. Hanushek). Die Zeit, 26.9.2013, pp. 87-88