An Assay definition describes the biology that is being tested when an experiment is run.  Several different Experiments (with different Measures) may be run from an Assay.<br /></p><p><br /></p><p>The Assay describes the biology in terms of a set of complex facts called Contexts.  Each context consists of a set of primitive facts (Context Items).  Each Context Item is made up from a single Attribute Value pair.  In the Assay definition the Context Items may be indeterminate - i.e. the values are constrained by the definition but are not specifically fixed. These indeterminate Context Items require specific data to be loaded at experiment time to fix the value.<br /></p><p><br /></p><p>For an Experiment specification, the indeterminate Contexts (not just the Items) are attached to Measures.  Thus the Measures can have Context that refers only to that Measure - a subset of the Assay Contexts, if you will.<br /></p><p><br /></p><p>The assay has document attached which are appropriate for ALL experiments run from that Assay definition.  The Assay is owned by a Team of People who would have permissions to edit the Assay.<br /></p>