# 2. Identify a target estimand under the model

Based on the causal graph, DoWhy finds all possible ways of identifying a desired causal effect based on the graphical model. It uses graph-based criteria and do-calculus to find potential ways find expressions that can identify the causal effect.

## 2.1. Supported identification criteria

Back-door criterion

Front-door criterion

Instrumental Variables

Mediation (Direct and indirect effect identification)

Different notebooks illustrate how to use these identification criteria. Check out the Simple Backdoor notebook for the back-door criterion, and the Simple IV notebook for the instrumental variable criterion.

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