Technical proficiency
Check SQL fluency beyond basic joins: window functions, CTEs, query tuning on large tables, plus dbt, Python (pandas), and BI tools like Looker, Tableau or Power BI.
Evidence to listen for
- Command of the languages, frameworks, and data tools the role actually uses
- Understands correctness, performance, and failure modes, not just syntax
- Has opinions on testing and can justify them
- Reads and reasons about code they did not write
Five-point scoring guide
Cannot work independently; fundamentals are missing.
Weak fundamentals; output needs heavy review.
Competent for the role; needs guidance on complex or unfamiliar work.
Strong practitioner; handles hard problems with little guidance.
Writes complex SQL from memory, names warehouse specifics (Snowflake, BigQuery), and describes dbt models or dashboards they built and maintained.