compare_ll_dsep.R

library(dplyr)
library(piecewiseSEM)

make_tests <- function(){
dat <- tibble(
  x <- runif(100),
  x1 = rnorm(100, x, sd = 0.001),
  x2 = rnorm(100, x, sd = 0.001),
  x3 = runif(100),
  y1 = rnorm(100, x1 + x3, sd = 0.1),
  y2 = rnorm(100, x2, sd = 0.1)
)

mod1 <- lm(y1 ~ x1 + x3, data = dat)
mod2 <- lm(y2 ~ x2, data = dat)

fit <- psem(mod1, mod2, data = dat)

cbind(
  fisherC(fit),
  LLchisq(fit)
) |> janitor::clean_names() |> as_tibble()
}


compare_tests <- purrr::map_df(1:1e3, ~make_tests())


a <- compare_tests |>
  mutate(match = (p_value>0.05) + (p_value_2>0.05),
         match = !(match==1))

#freq of match between fisher's c and ll chisq
sum(a$match)/nrow(a)