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arXiv 1106.0972math.STmath.PRstat.TH
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基于局部独立性的图模型反事实分析

Counterfactual analyses with graphical models based on local independence

Kjetil Røysland

摘要:

我们表明,一个可以执行因果推理的连续时间的情况下,使用随机分析的工具,在一个自然的方式。这为逆概率加权的正性条件提供了新的替代方案。在反事实情景中,决定观测频率的概率分布可以用所谓的鞅问题来描述。反事实和事实概率分布可以通过由随机微分方程给出的似然比来关联。我们可以根据原始观察结果对反事实场景进行推断,并根据此似然比进行重新加权。如果随机微分方程的解是一致可积的,这是可能的,这一性质可以通过比较相应的事实和反事实短期预测来确定。局部独立图是有向的,可能是循环的,表示充分自治的随机过程之间的短期预测的图。我们通过一个例子表明,这些图可以用来识别和提供一致的估计在连续时间的反事实参数。这类似于Judea Pearl如何使用图形信息来识别有限状态贝叶斯网络中的因果效应。

英文摘要:

We show that one can perform causal inference in a natural way for continuous-time scenarios using tools from stochastic analysis. This provides new alternatives to the positivity condition for inverse probability weighting. The probability distribution that would govern the frequency of observations in the counterfactual scenario can be characterized in terms of a so-called martingale problem. The counterfactual and factual probability distributions may be related through a likelihood ratio given by a stochastic differential equation. We can perform inference for counterfactual scenarios based on the original observations, re-weighted according to this likelihood ratio. This is possible if the solution of the stochastic differential equation is uniformly integrable, a property that can be determined by comparing the corresponding factual and counterfactual short-term predictions. Local independence graphs are directed, possibly cyclic, graphs that represent short-term prediction among sufficiently autonomous stochastic processes. We show through an example that these graphs can be used to identify and provide consistent estimators for counterfactual parameters in continuous time. This is analogous to how Judea Pearl uses graphical information to identify causal effects in finite state Bayesian networks.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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