The rationale of the CS is that migrants, during their everyday life, frequent a range of 'aggregation centres' (such as immigrant specific services, phone centres, churches, etc)., which can be used as first level unit of analysis to select migrants (the second level unit).
Children were defined as the first level unit of analysis, and school was the second level unit of analysis.
There could be dependence on the observations inside the second level unit [ 15] which could be the hospital or the type of ward.
For the second level (unit level), we fit random intercepts for each one of ten units and nested into the variable units random components for type of admission and reasons for admitting: sepsis syndrome, cardiac surgery and respiratory conditions.
Let N be the number of second level units and nj (j = 1,…, N) be the number of first level units in group j.
The fourth level units overlay and joint together, forming complex fifth level architectural units of channel filling divided by architectural boundaries of different levels.
> -wrap-foot> Pooled analyses combining data from all three countries, with deliveries as first level units and receiving countries as second level units, showed that, compared with the receiving country-born, women from Sub-Saharan Africa were at higher odds of severe maternal morbidity [adjusted odds ratio (AOR): 1.68: 95% CI: 1.46, 1.93].
This model did not reach convergence because of the high percentage (40%) of second-level units (family), including only one first-level unit (individual).
In brief, a three-step randomized sampling procedure was performed as follows: first, two urban districts and one suburb were drawn as the first-stage sample; second, three communities were selected as the second-level unit; and, finally, three neighborhoods were chosen as third-level unit.
When analysing the data of such cluster-randomized trials, a multilevel analysis should be applied in order to take into account the dependency of first-level units (i.e., subjects) within a second-level unit (i.e., a cluster).
Specifically, the data shows a nested structure, where the first-level units are the individuals and the second-level units are the families.
