synthetizeCausalEffect: Computes Average Causal Effects by Covariate Adjustment in...

In CausalFX: Methods for Estimating Causal Effects from Observational Data

Description

Computes the average causal effect (ACE) of a given treatment variable X on a given outcome Y for the models generated by simulateWitnessModel. This assumes the synthetic models are small enough, as adjustment is done by brute force calculation.

Usage

synthetizeCausalEffect(problem)

Arguments

problem

a cfx problem instance for the ACE of a given treatment X on a given outcome Y. This problem instance should have a fully specified causal model, including a graph and conditional probability tables. It must also be small enough so that the joint probability must have been pre-computed.

Details

The algorithm implemented is a naive one. When creating the cfx object, field num_v_max must be large enough so that the joint distribution is computed in advance. Only for relatively small models (approximately 20 variables in total) this will be feasible.

Value

A list containing three different types of estimand:

effect_real	the true ACE.
effect_naive	the result of a naive adjustment using all of the observed covariates.
effect_naive2	the result of a naive adjustment using no covariates.

Examples

## Generate a synthetic problem
problem <- simulateWitnessModel(p = 4, q = 4, par_max = 3, M = 1000)

## Idealized case: suppose we know the true distribution,
## get "exact" ACE estimands for different adjustment sets
sol_pop <- covsearch(problem, pop_solve = TRUE)
effect_pop <- synthetizeCausalEffect(problem)
cat(sprintf(
  "ACE (true) = %1.2f\nACE (adjusting for all) = %1.2f\nACE (adjusting for nothing) = %1.2f\n",
   effect_pop$effect_real, effect_pop$effect_naive, effect_pop$effect_naive2))

CausalFX documentation built on May 2, 2019, 5:39 a.m.