Educational researchers commonly use the rule of thumb of "design effect smaller than 2" as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models…

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…