Estimation de la variance pour l'enquête ELFE

Abstract

The 2011 Elfe cohort comprises more than 18,000 children whose parents consented to their inclusion. In each of the selected maternity units, targeted babies born during four specific periods representing each of the four seasons in 2011 were selected. The Elfe cohort was selected through a non-standard sampling design that is called cross-classified sampling, with independent selections of the sample of maternity units and of the sample of days. In this work, we propose unbiased variance estimators and we derive specific variance estimators adapted to the Elfe case. The results are illustrated and procedures in R, SAS and Stata are described.