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| While EI is essentially a measure of [[Mutual Information]], unlike traditional [[Information Theory]], effective information EI includes a [[do-operator]] in its definition, which involves an [[Intervention Operation]] on the input variable. Why is this intervention necessary? | | While EI is essentially a measure of [[Mutual Information]], unlike traditional [[Information Theory]], effective information EI includes a [[do-operator]] in its definition, which involves an [[Intervention Operation]] on the input variable. Why is this intervention necessary? |
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− | According to [[Judea Pearl]]’s [[Ladder of Causality]]<ref name=pearl_causality />, [[Causal Inference]] can be divided into three levels: association, [[Intervention]], and [[Counterfactuals]]. The higher the level, the stronger the causal features. Directly estimating [[Mutual Information]] from observational data measures the level of association. If we can [[intervene]] in the variables, i.e., set a variable to a specific value or make it follow a particular distribution, we move up to the intervention level. By introducing the [math]do[/math] operator in the definition of EI, we allow EI to capture causal features more effectively than [[Mutual Information]] alone. | + | According to [[Judea Pearl]]’s [[Ladder of Causality]]<ref name=pearl_causality />, [[Causal Inference]] can be divided into three levels: association, [[Intervention]], and [[Counterfactuals]]. The higher the level, the more apparent the causal characteristics. Directly estimating [[Mutual Information]] from observational data measures the level of association. If we can [[intervene]] in the variables, i.e., set a variable to a specific value or make it follow a particular distribution, we move up to the intervention level. By introducing the [math]do[/math] operator in the definition of EI, we allow EI to capture causal features more effectively than [[Mutual Information]] alone. |
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| From a practical perspective, incorporating the [[do-operator]] in EI’s calculation separates the data from the dynamics, eliminating the effect of the data distribution (i.e., [math]X[/math] distribution) on the EI measurement. In general [[Causal Graphs]], the [[do-operator]] cuts off all causal arrows pointing to the intervened variable, preventing [[Confounding Factors]] from creating [[Spurious Associations]]. Similarly, in EI's definition, the [[do-operator]] removes all causal arrows pointing to the cause variable [math]X[/math], including influences from other variables (both observable and unobservable). This ensures that EI captures the intrinsic characteristics of the dynamics itself. | | From a practical perspective, incorporating the [[do-operator]] in EI’s calculation separates the data from the dynamics, eliminating the effect of the data distribution (i.e., [math]X[/math] distribution) on the EI measurement. In general [[Causal Graphs]], the [[do-operator]] cuts off all causal arrows pointing to the intervened variable, preventing [[Confounding Factors]] from creating [[Spurious Associations]]. Similarly, in EI's definition, the [[do-operator]] removes all causal arrows pointing to the cause variable [math]X[/math], including influences from other variables (both observable and unobservable). This ensures that EI captures the intrinsic characteristics of the dynamics itself. |
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− | The introduction of the [[do-operator]] makes EI distinct from other information metrics. The key difference is that EI is solely a function of the [[Causal Mechanism]], which allows it to more precisely capture the essence of causality compared to other metrics like [[Transfer Entropy]]. However, this also means that EI requires knowledge of or access to the [[Causal Mechanism]], which may be challenging if only observational data is available. | + | The introduction of the [[do-operator]] makes EI distinct from other information metrics. The key difference is that EI is solely a function of the [[Causal Mechanism]], which allows it to more precisely capture the essence of causality compared to other metrics like [[Transfer Entropy]]. However, this also means that EI requires the knowledge of or access to the [[Causal Mechanism]], which may be challenging if only observational data is available. |
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| ==Why Intervene to Achieve a Uniform Distribution?== | | ==Why Intervene to Achieve a Uniform Distribution?== |