Data Index (DE + DS foundations)
Data roles fail in interviews for predictable reasons:
- weak SQL fundamentals under time
- hand-wavy data modeling
- ignoring quality/lineage/cost
- not turning ambiguity into a plan
Core skills by role
Data Engineer
- SQL + modeling
- batch and streaming pipelines
- orchestration
- data quality + lineage
- cost and reliability
Data Scientist
- metrics and experiments
- causal reasoning intuition
- storytelling and stakeholder influence
- practical modeling (when relevant)