Computes a placebo variant of our estimator using pre-treatment data only

Computes a placebo variant of our estimator using pre-treatment data only

Usage

synthdid_placebo(estimate, treated.fraction = NULL)

Arguments

estimate,

as output by synthdid_estimate

treated.fraction,

the fraction of pre-treatment data to use as a placebo treatment period Defaults to NULL, which indicates that it should be the fraction of post-treatment to pre-treatment data

Value

A placebo estimate using only pre-treatment data

Examples

# \donttest{
data(california_prop99)
setup <- panel.matrices(california_prop99)
tau.hat <- synthdid_estimate(setup$Y, setup$N0, setup$T0)

# Compute placebo estimate
tau.placebo <- synthdid_placebo(tau.hat)

# Should be close to zero if parallel trends holds
c(estimate = tau.hat, placebo = tau.placebo)
#>   estimate    placebo 
#> -15.603786  -1.667416 
# }