Kryssklassifiserte

Kryssklassifiserte is a Norwegian term meaning cross-classified. It describes data or objects that are assigned to two or more categorization dimensions that do not nest within each other. In other words, an item can belong to multiple categories across different axes, and there is no single hierarchical ordering that places all categories above or below others.

Fields that use kryssklassifisering include statistics, information science, bibliometrics, sociology, and market research. For example, in a library catalog a work might be indexed by both subject headings and language codes, creating a two-dimensional (or multi-dimensional) classification. In survey data, individuals may be categorized by both geographic region and occupation. Such structures produce cross-classified contingency tables where cells represent the intersection of categories from each dimension and many cells can be empty.

Analytical approaches for kryssklassifiserte data include log-linear models for contingency tables, and cross-classified multilevel models (CCMM) that model random effects associated with each classification dimension. Traditional two-way analyses and simple hierarchical models are often inappropriate because the categories are not nested.

Benefits of kryssklassifisering include richer description and flexible indexing, while challenges include data sparsity, interpretability, and model complexity. Adequate sample sizes and careful model selection are essential to draw valid inferences from cross-classified data.

Origin and usage: The term is used in Norwegian to describe a general statistical concept that is also discussed in English-language literature as cross-classification, cross-classified data, or cross-tabulation with non-nested factors.