Hierarchical linear models are applicable in situations where data have been collected from two (or more) different levels. Sociology's initial interest in such multilevel relationships can be traced back to Durkheim's research into the impact of community on suicide (Durkheim [1898] 1951). More recently, these models have been related to the topic of contextual analysis (Boyd and Iversen 1979), where researchers are interested in investigating linkages between micro-level and macro-level variables. Sociological theories have been classified into three groups according to the degree to which they incorporate multilevel variables (Coleman 1986). In one group, variation in a dependent variable is explained through independent variables obtained from the same social level (e.g., country, community, individual). In a second group, attempts are made to account for differences in a dependent variable at one level by examining variation in an independent variable at a higher level; and in a third...