Hire BI developers who build the semantic layer — not just reports on top of it. Most BI developers can build a chart. Fewer can design the dimensional model, define conformed metrics, implement row-level security, and optimize query performance for 500 concurrent users. The semantic layer is what separates "five versions of revenue" from "one trusted number."
Production BI requires: Dimensional modeling — star schema, conformed dimensions, slowly changing dimensions. Semantic layer — governed metric definitions, calculation groups, hierarchies. Performance — aggregations, query folding, composite models, partitioning. Governance — deployment pipelines, workspace management, data certification.