Sample Selectivity and the Validity of International Student Achievement Tests in Economic Research
---- Acknowledgements -----
Woessmann gratefully acknowledges the hospitality and support provided by the W. Glenn Campbell and Rita Ricardo-Campbell National Fellowship of the Hoover Institution, Stanford University. Support has also come from the Pact for Research and Innovation of the Leibniz Association. Hanushek has been supported by the Packard Humanities Institute. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.