Data quality for people who ship numbers

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Hands-on data quality for analysts who ship numbers: dimensions, profiling, dedupe, standards, time, checks, and a light scorecard.

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1 What bad data actually means Bad data is a shrug, not a diagnosis. Learn five practical quality dimensions (completeness, accuracy, consistency, timeliness, uniqueness) with workplace examples so you name the failure mode before you clean and make things quietly worse.
2 Profile before you polish Cleaning before you look is how silent bias sneaks into dashboards. Learn a lightweight profile of counts, nulls, ranges, and weird categories with SQL and Python so every polish step has a reason and a named quality dimension.
3 Deduping without destroying history Duplicates are identity problems, not a delete button. Learn natural versus surrogate keys, soft deletes, merge lineage, and validation checks so you collapse false twins without shredding history, audits, or revenue totals that should stay invariant.
4 Standardizing categories and names Category chaos turns dashboards into spelling bees. Learn canonical values, mapping tables, alias lists, and how to escape Other hell so groupbys stay honest and unmapped rates stay visible without enterprise MDM theater.
5 Dates, time zones, and fiscal calendars Time zones and fiscal calendars quietly break dashboards people trust. Learn to store UTC, display local time, separate calendar months from fiscal periods, and cast dates safely in SQL and Python before you ship a number. Scheduled · August 17, 2026
6 Validation checks you can automate Automated checks catch bad data before leadership does. Build small scripts for row counts, referential integrity, freshness, and yesterday versus last week sanity so every number you ship has a real safety net. Scheduled · August 18, 2026
7 Documenting quality so others trust you Trust needs a light paper trail, not a bureaucracy. Publish a simple data quality scorecard with owner, metrics, known issues, and next check so teammates can rely on your numbers without guessing in a crisis. Scheduled · August 19, 2026