A behind-the-scenes blog about research methods at Pew Research Center. For our latest findings, visit pewresearch.org. Identifying causal relationships from observational data is not easy. Still, ...

Central to the idea of variance components models is the idea of fixed and random effects. Each effect in a variance components model must be classified as either a fixed or a random effect. Fixed ...

Background: It is well known that individual-level social capital is positively associated with health, but most preceding studies have not fully controlled for an individual's time-invariant ...

This is a preview. Log in through your library . Abstract The Mantel-Haenszel test of treatment, response independence within strata in an s × t × r contingency table is reviewed. In the case of one ...