Correct Measurement-Error Bias

Why Correct for Measurement Error?

• In conjoint experiments, measurement error is pervasive but often overlooked.
  
• Respondents may:
  • Misread attributes
  • Misunderstand levels
  • Click randomly
  • Forget information across tasks
• As a result, respondents’ recorded choices often refelect random noise.
  
• This random error leads to attenuate true prefernces (or true effects).

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The Consequences of Ignoring Measurement Error

Without Correction	With Correction
Underestimates true preferences	Provides more accurate preferences
Falsely suggests indifference	Recovers meaningful trade-offs
Misleads theory building and application	Provides accurate, unbiased insights

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How projoint Corrects for Measurement Error

• Estimates the intra-respondent reliability (IRR) based on responses to a repeated task
• Adjusts marginal means (MMs) and average marginal component effects (AMCEs) accordingly
• Provides corrected estimates that better reflect respondents’ true preferences
• Corrected estimates reveal the true magnitude of effects, improving both theoretical and applied inferences in political science, marketing, and other fields.

✅ No additional respondent burden (just one repeated task)
✅ Minimal survey design changes
✅ Massive improvements in accuracy

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Key Takeaway

🧠 Measurement error systematically biases results.

🔥 Correcting for measurement error reveals true preferences, sharper trade-offs, and prevents misleading inferences.

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📚 Key Reference

• Clayton, Horiuchi, Kaufman, King, Komisarchik (Forthcoming).
  “Correcting Measurement Error Bias in Conjoint Survey Experiments.”
  Forthcoming, American Journal of Political Science.
  Pre-Print Available

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