Theory 20/Refinement
Dietary Effects Are Smaller
The claim
Dietary associations shrink when intake is measured by biomarkers rather than questionnaires, because self-report error is systematic.
01Mechanism
Misreporting is correlated with the outcome, biasing estimates away from the null.
02Prediction
Associations should attenuate with biomarker measurement.
03Refutation
Agreement would remove the measurement bias.