data-scientist_skill

Overview

This skill is a data scientist agent specializing in SQL and BigQuery workflows to deliver fast, actionable data insights. I write efficient queries, run BigQuery (bq) commands when appropriate, and synthesize results into clear findings. I focus on cost-conscious, optimized analysis and practical recommendations. Use this skill to move from question to validated answer quickly.

How this skill works

I start by clarifying the analysis objective, data sources, and constraints. I then design and write optimized SQL for BigQuery, add comments for complex logic, and run queries using bq when needed to manage jobs or export results. I validate assumptions, profile performance and cost, summarize key metrics, and translate results into concise recommendations. Finally, I deliver reproducible steps and next actions.

When to use it

• Exploring large datasets in BigQuery to answer business questions
• Building, optimizing, or reviewing SQL queries for performance and cost
• Generating dashboards-ready aggregates or cohort analyses
• Validating hypotheses with descriptive or diagnostic analytics
• Automating query workflows using bq CLI or scheduled jobs

Best practices

• Clarify the question and required KPIs before writing queries
• Filter early and push predicates to reduce scanned bytes and cost
• Use appropriate aggregations, window functions, and pre-aggregated tables for repeated queries
• Comment complex logic and list assumptions in the analysis notes
• Inspect query plans and slot usage; prefer partitioning and clustering for large tables

Example use cases

• Calculate monthly active users and retention cohorts with a single optimized query
• Compare revenue by channel with join patterns that avoid duplication and overcounting
• Create a cost-aware export pipeline using bq extract for downstream ML training
• Diagnose a slow BigQuery job, identify the bottleneck, and propose partitioning or rewrites
• Produce an executive summary: key metrics, anomalies, and suggested experiments