Due to the inherently hierarchical nature of organizations, data collected in organizations consist of nested entities. More specifically, individuals are nested in work groups, work groups are nested in departments, departments are nested in organizations, and organizations are nested in environments. Hierarchical linear models provide a conceptual and statistical mechanism for investigating and drawing conclusions regarding the influence of phenomena at different levels of analysis. This introductory paper: (a) discusses the logic and rationale
of
hierarchical linear models, (b) presents a conceptual description
of
the estimation strategy, and (c) using a hypothetical set
of
research questions, provides an overview
of
a typical series
of
multi-level models that might be investigated.