摘要：A Multilevel model is a statistical tool for analysing data that has a hierarchical data structure (in other words, data are nested within contexts). This paper describes what a multilevel model is, how it is described mathematically, the advantages of using this data analysis technique, and some practical issues to consider. We then move on to describe the application of multilevel models using two scenarios pertinent to researchers interested in clinical trial analysis and experimental psychopathology research. We describe how to use the software R to run these analyses.
