Multilevel data structures are ubiquitous in the assessment of differential item functioning (DIF), particularly in large-scale testing programs. There are a handful of DIF procures for researchers to select from that appropriately account for multilevel data structures. However, little, if any, work has been completed to extend a popular DIF…

Eleven indexes of rurality and their effect on the classification of Michigan's 83 counties were investigated. The indexes were based on different concepts of rurality: (1) percent of employment in agriculture, fishing, and forestry; (2) population density and distance to urban centers; and (3) economic conditions. Index rankings were compared to…

These two articles discuss clustering structure in the Cystic Fibrosis Document Collection, which is derived from the National Library of Medicine's MEDLINE file. The exhaustivity of four subject representations and two citation representations is examined, and descriptor-weight thresholds and similarity thresholds are used to compute…