Question

1. The fundamental problem of causal inference is the fact that one can only observe one outcome under one condition, not under both conditions simultaneously.   The fundamental problem notwithstanding, even if you cannot observe whether variable X causes outcome Y in any given individual, it can still be possible to figure out if variable X causes outcome Y on average. What two assumptions are necessary to make this claim?

Answer 1

Two assumptions are:

(1). Assumption of No interference which states that there is one unit donot affect the outcome of another unit and treatment assigned to one unit does not interfere witht the outcome of another unit.

(2). There is one version of treatment across all the individual in the study. Example let us consider teaching as a treatment. If a different teacher teaches in a significantly different way then we must consider it as a different treatment.