Under a general structural equation framework for causal inference, we provide a definition of the causal effect of a variable X on another variable Y, and propose an approach to estimate this causal effect via the use of instrumental variables.

翻译：根据因果推断的一般结构等式框架,我们界定了变数X对另一个变数Y的因果影响,并提议了一种办法,通过使用工具变量来估计这种因果影响。