Causal Catalog#

Assumptions#

Consistency#

Definition

The observed outcome \(Y\) for a unit is the same as the potential outcome \(Y(T=t)\) for that unit under the treatment that was actually observed \(T=t\).

Mathematical definition

\(Y = Y(T)\)

For binary treatment, that means:

  • \(Y = Y(1) \text{ if } T=1\)
  • \(Y = Y(0) \text{ if } T=0\)

Intuition/Examples

Activity 3 consistency scenarios

Exchangeability#

Definition

The distribution of \(Y(0)\) and \(Y(1)\) for the \(T=1\) and \(T=0\) groups are the same. Also known as ignorability.

Mathematical definition

\(Y(0), Y(1) \perp T\)

Intuition/Examples

Caffeine and exam performance exchangeability brainstorm (slide 12)

Study Designs#

Randomized Experiments#

Assumptions needed

  • Consistency
  • No interference

Assumptions ensured

  • Exchangeability

Causal quantities identified

  • Average treatment effect (ATE)

Pros/cons#

Advantages

Disadvantages

  • Mitigating the impact of confounding variables
  • Exchangeability is ensured
  • Ensure that the results are causal
  • Cost a lot
  • Some experiments cannot be randomized because of ethics
  • Potential biases in random assignment
  • It is not always possible to design randomized experiments for certain circumstances