An explanation of the General Observation Classes and "Special Purpose domains" might be in order. Maybe the concept map from the SDTM model (PDF page 8) or a modified version of it would be sufficient at this stage of the TIG.
In draft
Standards in this guide are end-to-end implementations of CDISC models designed to ensure the traceability and transparency of data across activities in the data lifecycle. Implementation of models per this guide in relation to activities which support collection, tabulation, analysis, and exchange of data are further described in the table below.
Observations
are imputed for analysis purposes, the imputed dates will be generated in the Analysis Data Model (ADaM) but not in the SDTM submission data sets.