Measure Billboard Campaign Impact: Design, Bias, Test Strategy
Measuring Billboard Impact on Brand Awareness
Scenario
A marketing team launched billboard ads in several cities and wants to estimate the campaign's causal impact on brand awareness compared to cities without billboards.
Assume brand awareness is measured via a short, consistent online survey (e.g., aided awareness: "Have you heard of Brand X?" yes/no) fielded in each city before and after the campaign. The campaign runs for 6–8 weeks, and you can choose which cities receive billboards.
Task
Design an experiment and analysis plan that covers:
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Hypotheses and outcome definition.
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Sampling and randomization strategy across cities.
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How to handle potential biases (e.g., city population differences, pre-existing brand affinity, spillovers, seasonality, concurrent marketing).
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The statistical test/model you would use after data collection and why.
Hints: Consider randomization, stratification/blocking, pre–post matching, and difference-in-differences.
Constraints & Assumptions
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Preserve the scope, facts, inputs, and requested outputs from the prompt above.
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If the prompt leaves a detail unspecified, state a reasonable assumption before relying on it.
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Keep the answer interview-ready: concise enough to present, but concrete enough to implement or evaluate.
Clarifying Questions to Ask
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Clarify the business objective, unit of analysis, time window, exposure definition, and primary metric.
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State assumptions about instrumentation, randomization, sample size, and data quality.
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Separate descriptive analysis from causal claims.
What a Strong Answer Covers
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A metric framework with primary, guardrail, and diagnostic metrics.
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A credible analysis or experiment design with clear assumptions and bias checks.
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SQL/statistical logic for segmentation, variance, confidence, and data validation where relevant.
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An actionable recommendation that explains trade-offs and next steps.
Follow-up Questions
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What sanity checks would you run before trusting the result?
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How would you handle novelty effects, seasonality, or selection bias?
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What decision would you make if metrics disagree?