The QDM is an information model defining relationships between patients and clinical concepts in a standardized format to enable electronic quality performance measurement. The model is the current structure for electronically representing quality measure concepts for interested parties involved in electronic quality measurement development and reporting. The QDM provides the language defining the criteria for clinical quality measurement. It allows the electronic definition of a clinical concept via its data elements and provides the vocabulary to relate them to each other. By relating attributes between data elements and using filtering functions, the QDM provides a method to construct complex clinical representations for eCQMs.