Category Archives: WTF

WTF is Short vs Long: What Is the Difference?

This article explains the difference between “long” and “short” positions in plain English, without the usual financial jargon. It breaks down how buying assets differs from selling what you don’t own, why professionals use both together, and why short positions carry unique risks. By the end, readers can confidently understand what investors mean when they say they’re long one thing and short another.

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WTF is the Fellegi–Sunter Model? A Practical Guide to Record Matching in an Uncertain World

The Fellegi–Sunter model is the foundational probabilistic framework for record linkage… deciding whether two imperfect records refer to the same real-world entity. Rather than enforcing brittle matching rules, it treats linkage as a problem of weighing evidence under uncertainty. By modelling how fields behave for true matches versus non-matches, it produces interpretable scores and explicit decision thresholds. Despite decades of new tooling and machine learning, most modern matching systems still rest on this logic… often without acknowledging it.

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WTF Is SCD? A Practical Guide to Slowly Changing Dimensions

Slowly Changing Dimensions (SCDs) are how data systems manage attributes that evolve without constantly rewriting history. They determine whether you keep only the latest value, preserve full historical versions, or maintain a limited snapshot of changes. The classic SCD types (0–3, plus hybrids) define different behaviours… from never updating values, to overwriting them, to keeping every version with timestamps. The real purpose of SCDs is to make an explicit choice about how truth should behave in your analytics: what should remain fixed, what should update, and what historical context matters. Modern data platforms make tracking changes easy, but they don’t make the design decisions for you. SCDs are ultimately the backbone of reliable, temporal, reality-preserving analytics.

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