articles & analytics notes

Explorations in SQL optimization, business intelligence architecture, statistical experimentation, and data storytelling.

3 published notes

5 min readSep 2026

Advanced SQL Window Functions for Cohort Retention Analysis

How to formulate month-over-month cohort retention matrices directly in PostgreSQL using Common Table Expressions (CTEs), DENSE_RANK, and LAG functions.

SQL & Relationalread note→

6 min readAug 2026

Designing Decision-Ready Executive Dashboards in Power BI & Tableau

Core principles for reducing cognitive load, architecting robust star schemas, and formulating reusable DAX time-intelligence calculations.

Business Intelligenceread note→

5 min readJul 2026

Statistical Significance & Common Pitfalls in Product A/B Testing

Understanding p-values, Type I/II errors, sample size power calculations, and why 'peeking' at metrics ruins experimental validity.

Statisticsread note→