Respondents in social and behavioral studies often belong to two or more non-nestedhigher-level groups of aggregation simultaneously, yielding the so-called cross-classified
data structure. For example, in education, students belong to the schools they attend and
the neighborhoods they live in, and there exists no exact nesting between the schools and
neighborhoods. The cross-classified multilevel model (CCMM; Goldstein, 1994; Rasbash
& Goldstein, 1994) was introduced as an extension of the standard multilevel model
to accommodate the prevalent cross-classified data. The CCMM has been mainly applied
in education to study the impacts of various contexts on certain outcomes, such as
the influence of schools and neighborhoods on smoking behaviors among adolescents
(Dunn, Richmond, Milliren, & Subramanian, 2015). However, applications of the CCMM
in other fields are relatively scant and little-known. One potential reason for this lack of
applications could be the limited availability of software programs that allow the easy
fit of the CCMM.
To advocate more applications of the CCMM in a broader spectrum, in this article, wefirst show the connections between the CCMM and several widely used psychometric
models, including the random effect item response theory (IRT) model (Van den Noortgate,
De Boeck, & Meulders, 2003), the model for rater effects (e.g., Murphy & Beretvas,
2015), the multitrait-multimethod (MTMM) model (Campbell & Fiske, 1959), and the
generalizability theory (G-theory) model (Shavelson & Webb, 1991). Then we review a
few modern applications of the CCMM, such as its applications to meta-analyses and
social network analysis (SNA).
To address the issue of software programs, we introduce a flexible and efficient Rpackage PLmixed (Jeon & Rockwood, 2017), and show how the above-mentioned related
models and applications of the CCMM can be estimated with PLmixed and other existing
R packages. Finally, we conclude that the CCMM would be applied more broadly
with the support of computer software such as PLmixed.