Sample sizes in cross-country growth regressions vary greatly, depending on data availability. But if the selected samples are not representative of the underlying population of nations in the world, ordinary least squares coefficients (OLS) may be biased. This paper re-examines the determinants...

Using logistic and multilevel logistic modelling we examine non-response at the school and pupil level to the important educational achievement survey Programme for International Student Assessment (PISA) for England. The analysis exploits unusually rich auxiliary information on all schools and...

In a national field experiment, the same questionnaires were administered simultaneously by RDD telephone interviewing, by the Internet with a probability sample, and by the Internet with a nonprobability sample of people who volunteered to do surveys for money. The probability samples were more...