2 IZA Discussion Papers
IZA Discussion Paper No. 8411
revised version published in: Journal of the Royal Statistical Society, Series A, 2018, 181 (4), 1057 - 1074
IZA Discussion Paper No. 4789
revised version published as 'Non-response biases in surveys of schoolchildren: the case of the English Programme for International Student Assessment (PISA) samples' in: Journal of the Royal Statistical Society, Series A (Statistics in Society), 2012, 175 (4), 915-938