The aim of the Elaboration Phase: to design the datamart schemas, ETL processes etc that are needed to support the requirements identified in the Inception Phase.
Driving the spikes deeper once requirements are more stable.
Schema refinement: star and snowflake schemas.
Metadata refinement: localization, column-level security, row-level security.
Data Processes: converting spreadsheet calculations into ETL processes.
BI Architectures: scale-out vs scale-up
Designing an architecture to handle the non-functional requirements (performance, hardware, data sources, acceptance criteria, etc).
Sizing: 10-10-10 rule. Benchmarking.
Identifying conforming dimensions in common with other datamarts.