IfcPerformanceHistory is used to document the actual performance of an occurrence instance over time. It includes machine-measured data from building automation systems and human-specified data such as task and resource usage. The data may represent actual conditions, predictions, or simulations. 

The realtime data tracked by performance history takes the form of property sets where all properties are based on time series. Unlike design-based data at occurrences and types, performance-driven data is time-sensitive and may change in realtime by some measurement device. Data may be captured at irregular intervals such as when values change beyond established thresholds, or at regular intervals of specified duration. 

IfcPerformanceHistory may be declared within a project using IfcRelDeclares where RelatingContext refers to the IfcProject and RelatedDefinitions includes the IfcPerformanceHistory. Default units (used for property sets) are indicated by the declaring project. Only top-level objects are declared; nested performance history objects (through IfcRelNests) do not participate in such relationship. 

The property sets relating to this entity are defined by IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. They are accessible by the IsDefinedBy inverse attribute. Applicable property sets are defined at assigned entities (primarily IfcDistributionElement subtypes) where IfcPropertySetTemplate.PropertySetType is PSET_PERFORMANCEDRIVEN. 

IfcPerformanceHistory may be classified using IfcRelAssociatesClassification where RelatingClassification refers to an IfcClassificationReference indicating a classification notation. Such classification notation may be used to identify the information such as an address within a building automation system, a work breakdown structure code for tasks, or a cost code for resource allocation. 

IfcPerformanceHistory may be decomposed into components using IfcRelNests where RelatingObject refers to the enclosing IfcPerformanceHistory and RelatedObjects contains one or more IfcPerformanceHistory components. Composition indicates breakdown of further detail and may correspond to the hierarchy of objects it represents. 

The Control Assignment concept template applies to this entity as shown in the table below: