Are You Confusing Correlation for Causation? Your Data (and Bottom Line) Depend on It.
- Maria Alice Maia

- Jul 8, 2024
- 3 min read
Let's cut to the chase. In the world of data, we're constantly bombarded with "insights" that promise to revolutionize our business. But how many of these are built on a house of cards, simply mistaking association for causation? Far too many, if you ask me. This isn't just "kindergarten data" – it's a fundamental misunderstanding that costs companies untold millions.
Today, I want to talk about something foundational: The Fundamental Problem of Causal Inference (FPCI) and why it's the bedrock of any truly data-driven decision.
Imagine you're running a major consumer goods brand. Your latest marketing campaign shows a massive spike in sales for your new premium chocolate bar. Naturally, your team is ecstatic! "The campaign caused the sales increase!" they exclaim. But did it? Or was it just associated with something else entirely?
This is where FPCI kicks in. At its core, to know if something (a "treatment," like our marketing campaign) causes an outcome (like increased sales), we need to compare two scenarios for the exact same unit (e.g., a specific customer, a sales region):
What happened when they received the treatment (saw the campaign)? (Y1i)
What would have happened if they had not received the treatment (never saw the campaign), all else being equal? (Y0i)
The snag? We can only ever observe one of these realities for any given unit. We can't simultaneously run the campaign for a customer and not run it for that same customer at the same time. This is the FPCI – the "missing data problem" of causality.
The "Doing Data Wrong" Scenario: The Red Wine Halo Effect
Think about the infamous "red wine health halo." For years, we heard that red wine was "good for the heart." Why? Because studies showed an association between moderate red wine consumption and better cardiovascular health. People jumped to the conclusion that red wine
caused good health.
The Wrong Way (Consumer Goods Example): Your marketing team launches a new campaign for an "artisanal, healthy" chocolate bar, emphasizing its rich cocoa content. Post-campaign, sales surge. The team concludes the campaign caused the increase. They double down on similar campaigns.
The Flaw: They looked only at the observed data. They didn't consider why people chose to buy the chocolate or see the ad. Perhaps affluent, health-conscious consumers, who already tend to make healthier choices and have higher disposable income (leading to higher purchases of premium goods), were more likely to be exposed to this specific campaign and were already inclined to buy such a product anyway. The "cause" isn't the campaign itself, but a shared underlying factor (like health consciousness and income) influencing both exposure to the ad and purchasing habits. This is confounding, plain and simple.
The Right Way (Leveraging Causal Inference): Instead of just observing the correlation, we need to apply methods that address the FPCI and potential confounders.
For instance, a savvy marketing lead would ask: "Are we sure this sales spike isn't just because our campaign disproportionately reached existing loyal customers who would have bought the chocolate anyway, or new customers who were already trending towards premium health products?"
What Managers Should Ask For:
Beyond "What happened?": Demand insights into "Why did it happen?" and "What would happen if we did X instead of Y?"
"What are the alternative explanations for this observed trend?" Challenge your data teams to identify and address potential confounders – those hidden variables influencing both your "treatment" (e.g., campaign exposure) and your "outcome" (e.g., sales).
"How robust is this conclusion if we account for self-selection or other biases?" Understand that observational data can be misleading if not handled with rigorous causal methods.
What Tech Professionals Should Deliver:
Move beyond simple correlations: Implement causal inference techniques like randomized controlled trials (RCTs) when possible, or sophisticated observational methods (e.g., matching, instrumental variables, difference-in-differences) when RCTs are not feasible.
Build Causal Diagrams (DAGs): Use these powerful tools to explicitly map out assumed causal relationships, identify confounders, and guide your analytical approach. Don't just run regressions;
reason about the data generating process!
Explain "Identification Strategies": Clearly articulate the assumptions being made to estimate causal effects and why those assumptions are defensible in your specific business context. This is how you bridge the gap between "tech-for-tech's-sake" and genuine business value.
The shift from correlation to causation isn't just academic; it’s about making smarter, more impactful business decisions, increasing gains, and drastically decreasing losses from misdirected efforts. My knowledge isn't mine to keep. Let's fix "doing data wrong" together.
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