Variance estimation in the analysis of clustered longitudinal survey data

This issue of Survey Methodology includes papers covering a variety of methodological subjects such as modeling and estimation, weighting and variance estimation, non-response and sampling.In the first paper of the issue, Skinner and Vieira investigate the effect of clustered sampling on variance estimation in longitudinal surveys. They present theoretical arguments and empirical evidence of the effects of ignoring clustering in longitudinal analyses, and find that these effects tend to be larger than for corresponding cross-sectional analyses. They also compare traditional survey sampling based methods to account for clustering in variance estimation to a multi­level modeling approach