Qm
Statistics

Sign-flip Simpson: homework and test scores

simpsons-paradoxconfoundingregression

Across all students in a K-12 school, plotting weekly homework hours against test scores gives a downward slope: students who do more homework score lower. Yet within each grade level, the slope is upward: more homework goes with higher scores.

Reconcile the negative school-wide slope with the positive within-grade slopes. Which relationship reflects the causal effect of homework on a student?

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Bad Controls and Post-Treatment BiasDirected Acyclic Graphs for CausalityPartial and Semipartial CorrelationThe Adaptive LassoBayesian Linear Regression

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