Between groups

Model for the group-level structure (second level). This term gets progressively rather vague as higher levels are added, it is suggested to be combined with an explicit indication of the grouping element of each level (i.e., class or school level).

Cross-level interaction

Higher level variables can directly influence lower level variables. This is usually displayed by an interaction between higher-level and lower-level variables.

Fixed effect, fixed Coefficient

Factor loadings and path coefficients that do not change across the units of the higher level.

Intraclass Correlation

Used to examine population similarity of the individuals of the same group. It is also a measure of the amount of population variance at the group level.

Multilevel model

A model comprising variables at multiple levels of a hierarchically structured population. Also called hierarchical model.

Random effect, random coefficient

Factor loadings and path coefficients that do not change across the units of the higher level.

Variance Component

Variances and covariances of the changeable coefficients.

Within groups

Model representing the structure at the lowest level, i.e. the individual (first) level.