Omitted Variable BiasThe commonest reason a regression coefficient is wrong.EconomicsOmitting a variable correlated with both theregressor and the outcome biases the estimate.Bias direction = sign(effect of Z on Y) × sign(corr of Z and X)Both positiveCoefficient biased upwardOverstated.Opposite signsBiased downwardZ unrelated to XNo biasOnly loses precision.THE COMMON MISTAKEAdding every available control variableChoosing controls by causal reasoningControlling for a variable on the causal path removes part of the very effect youare trying to measure.Draw the causal diagram before choosing controls. Which variables toinclude is a theory decision, not a statistical one.Omitted Variable Biaslearnposters.com
Omitted Variable Bias — printable business wall chart from LearnPosters. Free vector PDF, US Letter and A4.

What’s on the Omitted Variable Bias poster

The rule, 3 worked examples, and the mistake everyone makes.

Draw the causal diagram before choosing controls. Which variables to include is a theory decision, not a statistical one.

Questions about the Omitted Variable Bias poster

What’s on the Omitted Variable Bias poster?
The rule, 3 worked examples, and the mistake everyone makes. Omitting a variable correlated with both the regressor and the outcome biases the est…; Bias direction = sign(effect of Z on Y) × sign(corr of Z and X); Both positive = Coefficient biased upward; Opposite signs = Biased downward; Z unrelated to X = No bias; Common mistake: Adding every available control variable → Choosing controls by causal…. Draw the causal diagram before choosing controls. Which variables to include is a theory decision, not a statistical one.
Who is the Omitted Variable Bias poster for?
Omitted Variable Bias belongs to the Economics section rather than to a school year, because business is not something one grade owns. Anyone learning econometrics can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the Omitted Variable Bias poster?
Leaving out something that affects both X and Y biases the coefficient on X. A wall chart earns its place by being glanceable from where the work is happening, so Omitted Variable Bias belongs on the wall where that business work actually happens, within glancing distance, rather than filed away.
What other posters go with Omitted Variable Bias?
Regression, Correlation & Causation and Economic Data sit alongside Omitted Variable Bias in the Economics section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.RegressionCorrelation & CausationEconomic Data
Is the Omitted Variable Bias poster free to download and print?
Yes. Omitted Variable Bias downloads as a free PDF with no account, no email and no watermark, like everything else in the Economics section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the Omitted Variable Bias poster print at?
Omitted Variable Bias is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Omitted Variable Bias loses nothing.Printing guide

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