Correlation, Confounded
Marketing spend and revenue move together, convincingly. Slide to control for the season driving both, and watch the relationship thin out.
Correlation: 0.00
Under the hood
The slider partials out the confounder: both variables are regressed on the seasonal driver and progressively replaced by their residuals. What remains at 100% is the partial correlation — the relationship after the season has explained what it can.
Takeaway: before acting on a correlation, ask what moves both lines. Controlling for it is one slider here; in real work it is the whole job.
Why this matters
Most business metrics share drivers: seasonality, headcount, pricing changes, the economy. Two series that share a driver will correlate whether or not either causes the other. That's why "spend more, revenue follows" charts are so persuasive and so often wrong.
The slider here does what an analyst does with a regression: it removes the part of each variable the season can explain and looks at what's left. The leftover relationship, the partial correlation, is the honest read. Before acting on a correlation, the question is always the same: what moves both lines?
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