1
0
ml_measurement_error_public/irr/simex_sim.R
chainsawriot 6b19a39464
Add simulation using simex
And there is a great potential for overestimating the true `Bxy`
2022-07-26 15:41:30 +02:00

57 lines
1.9 KiB
R

##install.packages(c("purrr", "simex", "irr"))
.emulate_coding <- function(ground_truth, Q = 1) {
if (runif(1) > Q) {
return(sample(c(0, 1), size = 1, replace = TRUE))
} else {
return(ground_truth)
}
}
distort_gt <- function(x, Q = NULL) {
return(purrr::map_dbl(x, .emulate_coding, Q = Q))
}
N <- c(1000, 3600, 14400)
m <- c(75, 150, 300)
B0 <- c(0, 0.1, 0.3)
Bxy <- c(0.1, 0.2, 0.5)
Q <- c(.6, .8, .9)
conditions <- expand.grid(N, m, B0, Bxy, Q)
logistic <- function(x) {1/(1+exp(-1*x))}
.step <- function(Bxy, B0, Q, N, m) {
x <- rbinom(N, 1, 0.5)
y <- Bxy * x + rnorm(N, 0, .5) + B0
dx <- as.numeric(distort_gt(x, Q = Q))
randomx <- sample(x, m)
coder1x <- distort_gt(randomx, Q = Q)
coder2x <- distort_gt(randomx, Q = Q)
coding_data <- matrix(c(as.numeric(coder1x), as.numeric(coder2x)), nrow = 2, byrow = TRUE)
alpha <- irr::kripp.alpha(coding_data, method = "nominal")
estimated_q <- alpha$value^(1/2)
estimated_q2 <- alpha$value
res <- data.frame(x = as.factor(x), y = y, dx = as.factor(dx))
naive_mod <- glm(y~dx, data = res, x = TRUE, y = TRUE)
real_mod <- glm(y~x, data = res, x = TRUE, y = TRUE)
px <- matrix(c(estimated_q, 1-estimated_q, 1-estimated_q, estimated_q), nrow = 2)
colnames(px) <- levels(res$dx)
corrected_mod <- simex::mcsimex(naive_mod, SIMEXvariable = "dx", mc.matrix = px, jackknife.estimation = FALSE, B = 300)
px2 <- matrix(c(estimated_q2, 1-estimated_q2, 1-estimated_q2, estimated_q2), nrow = 2)
colnames(px2) <- levels(res$dx)
corrected_mod2 <- simex::mcsimex(naive_mod, SIMEXvariable = "dx", mc.matrix = px2, jackknife.estimation = FALSE, B = 300)
return(tibble::tibble(N, m, Q, Bxy, B0, estimated_q, naive_Bxy = as.numeric(coef(naive_mod)[2]), real_Bxy = as.numeric(coef(real_mod)[2]), corrected_Bxy = coef(corrected_mod)[2], corrected_Bxy2 = coef(corrected_mod2)[2]))
}
## res <- .step(0.2, 0, 0.8, N = 1000, m = 100)