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What is the potential outcome framework used to estimate in the context of schooling and wage?
What is the potential outcome framework used to estimate in the context of schooling and wage?
The causal effect of schooling on wage
What is the observed outcome in the context of schooling and wage, according to the potential outcome framework?
What is the observed outcome in the context of schooling and wage, according to the potential outcome framework?
Yi = Y0i + (Y1i − Y0i )Di
What is the average treatment effect on the treated (ATET) in the context of schooling and wage?
What is the average treatment effect on the treated (ATET) in the context of schooling and wage?
E[Y1i |Di = 1] − E[Y0i |Di = 1]
What is the assumption required to give regression a causal interpretation when the data are non-experimental?
What is the assumption required to give regression a causal interpretation when the data are non-experimental?
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What is the problem with using regression to estimate the causal effect of schooling on wage, in the absence of additional assumptions?
What is the problem with using regression to estimate the causal effect of schooling on wage, in the absence of additional assumptions?
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What is the consequence of omitting a relevant variable from a regression model, in the context of schooling and wage?
What is the consequence of omitting a relevant variable from a regression model, in the context of schooling and wage?
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What is the Constant Effect Model in the context of schooling and wage?
What is the Constant Effect Model in the context of schooling and wage?
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Why is it problematic to use a bad control in a regression model, in the context of schooling and wage?
Why is it problematic to use a bad control in a regression model, in the context of schooling and wage?
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What is the main characteristic of bad controls in a regression analysis?
What is the main characteristic of bad controls in a regression analysis?
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What is the primary concern with using a bad control in a causal analysis?
What is the primary concern with using a bad control in a causal analysis?
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In a DAG, what is the effect of conditioning on a collider variable?
In a DAG, what is the effect of conditioning on a collider variable?
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What is the assumption required for a constant effect model to hold?
What is the assumption required for a constant effect model to hold?
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How can omitted variable bias arise in a regression analysis with a binary outcome?
How can omitted variable bias arise in a regression analysis with a binary outcome?
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What is the assumption that E[vi |Xi , Di ] = E[vi |Xi ] in the context of regression and causality?
What is the assumption that E[vi |Xi , Di ] = E[vi |Xi ] in the context of regression and causality?
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What is the purpose of the conditional independence assumption in a regression analysis?
What is the purpose of the conditional independence assumption in a regression analysis?
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What is the main difference between the traditional assumption of independence and the Conditional Independence Assumption (CIA)?
What is the main difference between the traditional assumption of independence and the Conditional Independence Assumption (CIA)?
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In a causal analysis, what is the difference between a direct and indirect effect of a treatment?
In a causal analysis, what is the difference between a direct and indirect effect of a treatment?
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What is the interpretation of the regression coefficients multiplying the controls in a regression model?
What is the interpretation of the regression coefficients multiplying the controls in a regression model?
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What is the role of a DAG in identifying bad controls?
What is the role of a DAG in identifying bad controls?
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What is the problem with including 'bad controls' in a regression model?
What is the problem with including 'bad controls' in a regression model?
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What is the Constant Effect Model in the context of regression and causality?
What is the Constant Effect Model in the context of regression and causality?
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What is the implication of the coefficient of d being almost 0 in the regression of v on x and d?
What is the implication of the coefficient of d being almost 0 in the regression of v on x and d?
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What is the main difference between regression and causality?
What is the main difference between regression and causality?
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What is the implication of including 'bad controls' in a regression model with binary outcomes?
What is the implication of including 'bad controls' in a regression model with binary outcomes?
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What is the formula for the regression coefficient in the bivariate case?
What is the formula for the regression coefficient in the bivariate case?
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What is the purpose of 'partialling out' other variables in the multivariate regression model?
What is the purpose of 'partialling out' other variables in the multivariate regression model?
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What is the consequence of omitting a variable X from the regression model when the population model is Yi = β0 + τDi + γXi + εi?
What is the consequence of omitting a variable X from the regression model when the population model is Yi = β0 + τDi + γXi + εi?
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What is the Conditional Independence Assumption (CIA) in the context of regression analysis?
What is the Conditional Independence Assumption (CIA) in the context of regression analysis?
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What is the Constant Effect Model in regression analysis?
What is the Constant Effect Model in regression analysis?
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What are 'bad controls' in the context of regression analysis?
What are 'bad controls' in the context of regression analysis?
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What is the main challenge in analyzing binary outcomes in regression analysis?
What is the main challenge in analyzing binary outcomes in regression analysis?
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How does the omission of a variable X affect the estimator of the coefficient of D in the regression of Y on D?
How does the omission of a variable X affect the estimator of the coefficient of D in the regression of Y on D?
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What is the primary assumption of the Constant Effect Model, and how is it related to regression analysis?
What is the primary assumption of the Constant Effect Model, and how is it related to regression analysis?
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How does the Conditional Independence Assumption (CIA) relate to the concept of causality in regression analysis?
How does the Conditional Independence Assumption (CIA) relate to the concept of causality in regression analysis?
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What is the problem of bad controls in regression analysis, and how can it lead to biased estimates?
What is the problem of bad controls in regression analysis, and how can it lead to biased estimates?
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What is omitted variable bias, and how can it be addressed in regression analysis?
What is omitted variable bias, and how can it be addressed in regression analysis?
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What is the difference between a binary outcome and a continuous outcome in regression analysis, and how do the assumptions differ?
What is the difference between a binary outcome and a continuous outcome in regression analysis, and how do the assumptions differ?
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How can the F-statistic and R-squared values be used to evaluate the goodness of fit of a regression model?
How can the F-statistic and R-squared values be used to evaluate the goodness of fit of a regression model?
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What is the role of the residual plot in regression analysis, and how can it be used to identify potential problems?
What is the role of the residual plot in regression analysis, and how can it be used to identify potential problems?
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How can the Coef. column in the regression output be used to interpret the effect of the independent variable on the dependent variable?
How can the Coef. column in the regression output be used to interpret the effect of the independent variable on the dependent variable?
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Study Notes
Regression and Causality
- Regression is not necessarily causal, and to give it a causal interpretation, we need an additional assumption.
- The observed outcome can be decomposed into the average treatment effect on the treated and selection bias.
- The potential outcome framework is used to state the causal effect of schooling on wage.
Bad Controls
- Bad controls are variables that introduce bias when controlled for, but leaving them out is fine.
- Bad controls are often variables that are themselves outcomes of the treatment.
- Good controls are variables that can be thought of as having been fixed before the treatment assignment.
- Example of bad control: a college (yes/no) and occupation (blue/white-collar) setting.
- Bad control means that a comparison of earnings conditional on the occupation may not have a causal interpretation, even if college is randomized.
- A DAG (directed acyclic graph) is more intuitive than a formal derivation to understand the bad control problem.
- The bad control problem is a case where a DAG is more intuitive than a formal derivation.
Regression Fundamentals
- The mechanical properties of regression are universal features of the population regression and its sample analogue that have nothing to do with a researcher's interpretation of the output.
- Regression coefficients change as covariates are added or removed from the model.
- Bivariate case: β = Cov(Yi, Xi) / Var(Xi).
- Multivariate case: βk = Cov(Yi, X̃ki) / Var(X̃ki), where X̃ki is residual from regression of Xki on all other covariates.
- Omitted variable bias: the estimator of the coefficient of D in the regression of Y on D is biased if an omitted variable X is correlated with D and affects Y.
Summarizing Comments
- The CIA (conditional independence assumption) is a weaker and more focused assumption than the traditional assumption that all regressors are independent of v.
- Focus is on identifying one causal effect, not on obtaining unbiased estimates for all right-hand side variables.
- There is a clear distinction between cause and controls on the right-hand side of the regression.
- The regression coefficients multiplying the controls have no causal interpretation.
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Description
This quiz covers the concept of regression and causality in the context of binary outcomes, using the example of schooling decisions and their effect on wages.