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add mle methods from carroll

This commit is contained in:
Nathan TeBlunthuis 2022-06-30 19:00:35 -07:00
parent 003733f22f
commit 588bdd7ed7
5 changed files with 318 additions and 55 deletions

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@ -50,8 +50,8 @@ simulate_data <- function(N, m, B0=0, Bxy=0.2, Bgy=-0.2, Bgx=0.2, y_explained_va
}
df <- df[,w_pred:=x]
df <- df[sample(1:N,(1-prediction_accuracy)*N),w_pred:=(w_pred-1)**2]
w <- predict(glm(x ~ w_pred,data=df,family=binomial(link='logit')),type='response')
df <- df[,':='(w=w, w_pred = w_pred)]
return(df)
}
@ -61,15 +61,20 @@ parser <- add_argument(parser, "--N", default=500, help="number of observations
parser <- add_argument(parser, "--m", default=100, help="m the number of ground truth observations")
parser <- add_argument(parser, "--seed", default=4321, help='seed for the rng')
parser <- add_argument(parser, "--outfile", help='output file', default='example_1.feather')
parser <- add_argument(parser, "--y_explained_variance", help='what proportion of the variance of y can be explained?', default=0.005)
parser <- add_argument(parser, "--gx_explained_variance", help='what proportion of the variance of x can be explained by g?', default=0.15)
parser <- add_argument(parser, "--prediction_accuracy", help='how accurate is the predictive model?', default=0.73)
args <- parse_args(parser)
B0 <- 0
Bxy <- 0.2
Bgy <- -0.2
Bgx <- 0.5
Bgx <- 0.4
df <- simulate_data(args$N, args$m, B0, Bxy, Bgy, Bgx, seed=args$seed, y_explained_variance = 0.025, gx_explained_variance = 0.15)
result <- list('N'=args$N,'m'=args$m,'B0'=B0,'Bxy'=Bxy,'Bgy'=Bgy, 'Bgx'=Bgx, 'seed'=args$seed)
df <- simulate_data(args$N, args$m, B0, Bxy, Bgy, Bgx, seed=args$seed, y_explained_variance = args$y_explained_variance, gx_explained_variance = args$gx_explained_variance, prediction_accuracy=args$prediction_accuracy)
result <- list('N'=args$N,'m'=args$m,'B0'=B0,'Bxy'=Bxy,'Bgy'=Bgy, 'Bgx'=Bgx, 'seed'=args$seed, 'y_explained_variance' = args$y_explained_variance, 'gx_explained_variance' = args$gx_explained_variance, "prediction_accuracy"=args$prediction_accuracy)
outline <- run_simulation(df, result)
outfile_lock <- lock(paste0(args$outfile, '_lock'),exclusive=TRUE)

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@ -31,68 +31,70 @@ source("simulation_base.R")
## one way to do it is by adding correlation to x.obs and y that isn't in w.
## in other words, the model is missing an important feature of x.obs that's related to y.
simulate_data <- function(N, m, B0, Bxy, Bgy, Bkx, Bgx, seed, xy.explained.variance=0.01, u.explained.variance=0.1){
simulate_data <- function(N, m, B0, Bxy, Bgy, seed, y_explained_variance=0.025, prediction_accuracy=0.73, accuracy_imbalance_difference=0.3){
set.seed(seed)
## the true value of x
g <- rbinom(N, 1, 0.5)
# make w and y dependent
u <- rnorm(N,0,)
g <- rbinom(N, 1, 0.5)
x <- rbinom(N, 1, 0.5)
xprime <- Bgx * g + rnorm(N,0,1)
y.var.epsilon <- (var(Bgy * g) + var(Bxy *x) + 2*cov(Bgy*g,Bxy*x)) * ((1-y_explained_variance)/y_explained_variance)
y.epsilon <- rnorm(N, sd = sqrt(y.var.epsilon))
y <- Bgy * g + Bxy * x + y.epsilon
k <- Bkx*xprime + rnorm(N,0,1.5) + 1.1*Bkx*u
df <- data.table(x=x,y=y,g=g)
x <- as.integer(logistic(scale(xprime)) > 0.5)
y <- Bxy * x + Bgy * g + B0 + u + rnorm(N, 0, 1)
df <- data.table(x=x,k=k,y=y,g=g)
w.model <- glm(x ~ k,df, family=binomial(link='logit'))
if( m < N){
if(m < N){
df <- df[sample(nrow(df), m), x.obs := x]
} else {
df <- df[, x.obs := x]
}
df[, x.obs := x.obs]
df <- df[,w_pred:=x]
w <- predict(w.model, df) + rnorm(N, 0, 1)
## y = B0 + B1x + e
pg <- mean(g)
px <- mean(x)
accuracy_imbalance_ratio <- (prediction_accuracy + accuracy_imbalance_difference/2) / (prediction_accuracy - accuracy_imbalance_difference/2)
df[,':='(w=w, w_pred = as.integer(w>0.5),u=u)]
# this works because of conditional probability
accuracy_g0 <- prediction_accuracy / (pg*(accuracy_imbalance_ratio) + (1-pg))
accuracy_g1 <- accuracy_imbalance_ratio * accuracy_g0
dfg0 <- df[g==0]
ng0 <- nrow(dfg0)
dfg1 <- df[g==1]
ng1 <- nrow(dfg1)
dfg0 <- dfg0[sample(ng0, (1-accuracy_g0)*ng0), w_pred := (w_pred-1)**2]
dfg1 <- dfg1[sample(ng1, (1-accuracy_g1)*ng1), w_pred := (w_pred-1)**2]
df <- rbind(dfg0,dfg1)
w <- predict(glm(x ~ w_pred,data=df,family=binomial(link='logit')),type='response')
df <- df[,':='(w=w, w_pred = w_pred)]
return(df)
}
schennach <- function(df){
fwx <- glm(x.obs~w, df, family=binomial(link='logit'))
df[,xstar_pred := predict(fwx, df)]
gxt <- lm(y ~ xstar_pred+g, df)
}
parser <- arg_parser("Simulate data and fit corrected models")
parser <- add_argument(parser, "--N", default=5000, help="number of observations of w")
parser <- add_argument(parser, "--m", default=200, help="m the number of ground truth observations")
parser <- add_argument(parser, "--seed", default=432, help='seed for the rng')
parser <- add_argument(parser, "--outfile", help='output file', default='example_2.feather')
parser <- add_argument(parser, "--y_explained_variance", help='what proportion of the variance of y can be explained?', default=0.01)
parser <- add_argument(parser, "--prediction_accuracy", help='how accurate is the predictive model?', default=0.73)
parser <- add_argument(parser, "--accuracy_imbalance_difference", help='how much more accurate is the predictive model for one class than the other?', default=0.3)
args <- parse_args(parser)
B0 <- 0
Bxy <- 0.2
Bgy <- 0
Bkx <- 2
Bgx <- 0
Bgy <- -0.2
df <- simulate_data(args$N, args$m, B0, Bxy, Bgy, args$seed, args$y_explained_variance, args$prediction_accuracy, args$accuracy_imbalance_difference)
result <- list('N'=args$N,'m'=args$m,'B0'=B0,'Bxy'=Bxy,'Bgy'=Bgy, 'seed'=args$seed, 'y_explained_variance'=args$y_explained_variance, 'prediction_accuracy'=args$prediction_accuracy, 'accuracy_imbalance_difference'=args$accuracy_imbalance_difference)
outline <- run_simulation_depvar(df=df, result)
outline <- run_simulation(simulate_data(args$N, args$m, B0, Bxy, Bgy, Bkx, Bgx, args$seed)
,list('N'=args$N,'m'=args$m,'B0'=B0,'Bxy'=Bxy,'Bgy'=Bgy, 'Bkx'=Bkx, 'Bgx'=Bgx, 'seed'=args$seed))
outfile_lock <- lock(paste0(args$outfile, '_lock'),exclusive=TRUE)
if(file.exists(args$outfile)){

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@ -0,0 +1,113 @@
### EXAMPLE 1: demonstrates how measurement error can lead to a type sign error in a covariate
### What kind of data invalidates fong + tyler?
### Even when you have a good predictor, if it's biased against a covariate you can get the wrong sign.
### Even when you include the proxy variable in the regression.
### But with some ground truth and multiple imputation, you can fix it.
library(argparser)
library(mecor)
library(ggplot2)
library(data.table)
library(filelock)
library(arrow)
library(Amelia)
library(Zelig)
library(predictionError)
options(amelia.parallel="no",
amelia.ncpus=1)
setDTthreads(40)
source("simulation_base.R")
## SETUP:
### we want to estimate x -> y; x is MAR
### we have x -> k; k -> w; x -> w is used to predict x via the model w.
### A realistic scenario is that we have an NLP model predicting something like "racial harassment" in social media comments
### The labels x are binary, but the model provides a continuous predictor
### simulation:
#### how much power do we get from the model in the first place? (sweeping N and m)
####
## one way to do it is by adding correlation to x.obs and y that isn't in w.
## in other words, the model is missing an important feature of x.obs that's related to y.
simulate_data <- function(N, m, B0, Bxy, Bgy, seed, prediction_accuracy=0.73, accuracy_imbalance_difference=0.3){
set.seed(seed)
# make w and y dependent
g <- rbinom(N, 1, 0.5)
x <- rbinom(N, 1, 0.5)
ystar <- Bgy * g + Bxy * x
y <- rbinom(N,1,logistic(ystar))
# glm(y ~ x + g, family="binomial")
df <- data.table(x=x,y=y,ystar=ystar,g=g)
if(m < N){
df <- df[sample(nrow(df), m), y.obs := y]
} else {
df <- df[, y.obs := y]
}
df <- df[,w_pred:=y]
pg <- mean(g)
accuracy_imbalance_ratio <- (prediction_accuracy + accuracy_imbalance_difference/2) / (prediction_accuracy - accuracy_imbalance_difference/2)
# this works because of conditional probability
accuracy_g0 <- prediction_accuracy / (pg*(accuracy_imbalance_ratio) + (1-pg))
accuracy_g1 <- accuracy_imbalance_ratio * accuracy_g0
dfg0 <- df[g==0]
ng0 <- nrow(dfg0)
dfg1 <- df[g==1]
ng1 <- nrow(dfg1)
dfg0 <- dfg0[sample(ng0, (1-accuracy_g0)*ng0), w_pred := (w_pred-1)**2]
dfg1 <- dfg1[sample(ng1, (1-accuracy_g1)*ng1), w_pred := (w_pred-1)**2]
df <- rbind(dfg0,dfg1)
wmod <- glm(y.obs ~ w_pred,data=df[!is.null(y.obs)],family=binomial(link='logit'))
w <- predict(wmod,df,type='response')
df <- df[,':='(w=w)]
return(df)
}
parser <- arg_parser("Simulate data and fit corrected models")
parser <- add_argument(parser, "--N", default=5000, help="number of observations of w")
parser <- add_argument(parser, "--m", default=200, help="m the number of ground truth observations")
parser <- add_argument(parser, "--seed", default=4321, help='seed for the rng')
parser <- add_argument(parser, "--outfile", help='output file', default='example_2.feather')
parser <- add_argument(parser, "--y_explained_variance", help='what proportion of the variance of y can be explained?', default=0.005)
parser <- add_argument(parser, "--prediction_accuracy", help='how accurate is the predictive model?', default=0.73)
parser <- add_argument(parser, "--accuracy_imbalance_difference", help='how much more accurate is the predictive model for one class than the other?', default=0.3)
args <- parse_args(parser)
B0 <- 0
Bxy <- 0.2
Bgy <- -0.2
df <- simulate_data(args$N, args$m, B0, Bxy, Bgy, args$seed, args$prediction_accuracy, args$accuracy_imbalance_difference)
result <- list('N'=args$N,'m'=args$m,'B0'=B0,'Bxy'=Bxy,'Bgy'=Bgy, 'seed'=args$seed, 'y_explained_variance'=args$y_explained_variance, 'prediction_accuracy'=args$prediction_accuracy, 'accuracy_imbalance_difference'=args$accuracy_imbalance_difference)
outline <- run_simulation_depvar(df=df, result)
outfile_lock <- lock(paste0(args$outfile, '_lock'),exclusive=TRUE)
if(file.exists(args$outfile)){
logdata <- read_feather(args$outfile)
logdata <- rbind(logdata,as.data.table(outline))
} else {
logdata <- as.data.table(outline)
}
print(outline)
write_feather(logdata, args$outfile)
unlock(outfile_lock)

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@ -17,12 +17,12 @@ example_1.feather: example_1_jobs
sbatch --wait --verbose --array=3001-6001 run_simulation.sbatch 0 example_1_jobs
example_2_jobs: example_2.R
grid_sweep.py --command "Rscript example_2.R" --arg_dict '{"N":${Ns},"m":${ms}, "seed":${seeds}, "outfile":["example_2.feather"]}' --outfile example_2_jobs
grid_sweep.py --command "Rscript 02_indep_differential.R" --arg_dict '{"N":${Ns},"m":${ms}, "seed":${seeds}, "outfile":["example_2.feather"]}' --outfile example_2_jobs
example_2.feather: example_2_jobs
rm -f example_2.feather
sbatch --wait --verbose --array=1-3000 run_simulation.sbatch 0 example_2_jobs
# sbatch --wait --verbose --array=3001-6001 run_simulation.sbatch 0 example_2_jobs
sbatch --wait --verbose --array=3001-6001 run_simulation.sbatch 0 example_2_jobs
example_2_B_jobs: example_2_B.R
grid_sweep.py --command "Rscript example_2_B.R" --arg_dict '{"N":${Ns},"m":${ms}, "seed":${seeds}, "outfile":["example_2_B.feather"]}' --outfile example_2_B_jobs

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@ -4,9 +4,164 @@ options(amelia.parallel="no",
amelia.ncpus=1)
library(Amelia)
library(Zelig)
library(stats4)
## This uses the pseudolikelihood approach from Carroll page 349.
## assumes MAR
## assumes differential error, but that only depends on Y
## inefficient, because pseudolikelihood
logistic.correction.pseudo <- function(df){
p1.est <- mean(df[w_pred==1]$y.obs==1,na.rm=T)
p0.est <- mean(df[w_pred==0]$y.obs==0,na.rm=T)
nll <- function(B0, Bxy, Bgy){
probs <- (1 - p0.est) + (p1.est + p0.est - 1)*plogis(B0 + Bxy * df$x + Bgy * df$g)
part1 = sum(log(probs[df$w_pred == 1]))
part2 = sum(log(1-probs[df$w_pred == 0]))
return(-1*(part1 + part2))
}
mlefit <- stats4::mle(minuslogl = nll, start = list(B0=0, Bxy=0.0, Bgy=0.0))
return(mlefit)
}
## This uses the likelihood approach from Carroll page 353.
## assumes that we have a good measurement error model
logistic.correction.liklihood <- function(df){
## liklihood for observed responses
nll <- function(B0, Bxy, Bgy, gamma0, gamma_y, gamma_g){
df.obs <- df[!is.na(y.obs)]
p.y.obs <- plogis(B0 + Bxy * df.obs$x + Bgy*df.obs$g)
p.y.obs[df.obs$y==0] <- 1-p.y.obs[df.obs$y==0]
p.s.obs <- plogis(gamma0 + gamma_y * df.obs$y + gamma_g*df.obs$g)
p.s.obs[df.obs$w_pred==0] <- 1 - p.s.obs[df.obs$w_pred==0]
p.obs <- p.s.obs * p.y.obs
df.unobs <- df[is.na(y.obs)]
p.unobs.1 <- plogis(B0 + Bxy * df.unobs$x + Bgy*df.unobs$g)*plogis(gamma0 + gamma_y + gamma_g*df.unobs$g)
p.unobs.0 <- (1-plogis(B0 + Bxy * df.unobs$x + Bgy*df.unobs$g))*plogis(gamma0 + gamma_g*df.unobs$g)
p.unobs <- p.unobs.1 + p.unobs.0
p.unobs[df.unobs$w_pred==0] <- 1 - p.unobs[df.unobs$w_pred==0]
p <- c(p.obs, p.unobs)
return(-1*(sum(log(p))))
}
mlefit <- stats4::mle(minuslogl = nll, start = list(B0=1, Bxy=0,Bgy=0, gamma0=5, gamma_y=0, gamma_g=0))
return(mlefit)
}
logistic <- function(x) {1/(1+exp(-1*x))}
run_simulation_depvar <- function(df, result){
accuracy <- df[,mean(w_pred==y)]
result <- append(result, list(accuracy=accuracy))
(model.true <- glm(y ~ x + g, data=df,family=binomial(link='logit')))
true.ci.Bxy <- confint(model.true)['x',]
true.ci.Bgy <- confint(model.true)['g',]
result <- append(result, list(Bxy.est.true=coef(model.true)['x'],
Bgy.est.true=coef(model.true)['g'],
Bxy.ci.upper.true = true.ci.Bxy[2],
Bxy.ci.lower.true = true.ci.Bxy[1],
Bgy.ci.upper.true = true.ci.Bgy[2],
Bgy.ci.lower.true = true.ci.Bgy[1]))
(model.feasible <- glm(y.obs~x+g,data=df,family=binomial(link='logit')))
feasible.ci.Bxy <- confint(model.feasible)['x',]
result <- append(result, list(Bxy.est.feasible=coef(model.feasible)['x'],
Bxy.ci.upper.feasible = feasible.ci.Bxy[2],
Bxy.ci.lower.feasible = feasible.ci.Bxy[1]))
feasible.ci.Bgy <- confint(model.feasible)['g',]
result <- append(result, list(Bgy.est.feasible=coef(model.feasible)['g'],
Bgy.ci.upper.feasible = feasible.ci.Bgy[2],
Bgy.ci.lower.feasible = feasible.ci.Bgy[1]))
(model.naive <- glm(w_pred~x+g, data=df, family=binomial(link='logit')))
naive.ci.Bxy <- confint(model.naive)['x',]
naive.ci.Bgy <- confint(model.naive)['g',]
result <- append(result, list(Bxy.est.naive=coef(model.naive)['x'],
Bgy.est.naive=coef(model.naive)['g'],
Bxy.ci.upper.naive = naive.ci.Bxy[2],
Bxy.ci.lower.naive = naive.ci.Bxy[1],
Bgy.ci.upper.naive = naive.ci.Bgy[2],
Bgy.ci.lower.naive = naive.ci.Bgy[1]))
(model.naive.cont <- lm(w~x+g, data=df))
naivecont.ci.Bxy <- confint(model.naive.cont)['x',]
naivecont.ci.Bgy <- confint(model.naive.cont)['g',]
## my implementatoin of liklihood based correction
mod.caroll.lik <- logistic.correction.liklihood(df)
coef <- coef(mod.caroll.lik)
ci <- confint(mod.caroll.lik)
result <- append(result,
list(Bxy.est.mle = coef['Bxy'],
Bxy.ci.upper.mle = ci['Bxy','97.5 %'],
Bxy.ci.lower.mle = ci['Bxy','2.5 %'],
Bgy.est.mle = coef['Bgy'],
Bgy.ci.upper.mle = ci['Bgy','97.5 %'],
Bgy.ci.lower.mle = ci['Bgy','2.5 %']))
## my implementatoin of liklihood based correction
mod.caroll.pseudo <- logistic.correction.pseudo(df)
coef <- coef(mod.caroll.pseudo)
ci <- confint(mod.caroll.pseudo)
result <- append(result,
list(Bxy.est.pseudo = coef['Bxy'],
Bxy.ci.upper.pseudo = ci['Bxy','97.5 %'],
Bxy.ci.lower.pseudo = ci['Bxy','2.5 %'],
Bgy.est.pseudo = coef['Bgy'],
Bgy.ci.upper.pseudo = ci['Bgy','97.5 %'],
Bgy.ci.lower.pseudo = ci['Bgy','2.5 %']))
# amelia says use normal distribution for binary variables.
amelia.out.k <- amelia(df, m=200, p2s=0, idvars=c('y','ystar','w_pred'))
mod.amelia.k <- zelig(y.obs~x+g, model='ls', data=amelia.out.k$imputations, cite=FALSE)
(coefse <- combine_coef_se(mod.amelia.k, messages=FALSE))
est.x.mi <- coefse['x','Estimate']
est.x.se <- coefse['x','Std.Error']
result <- append(result,
list(Bxy.est.amelia.full = est.x.mi,
Bxy.ci.upper.amelia.full = est.x.mi + 1.96 * est.x.se,
Bxy.ci.lower.amelia.full = est.x.mi - 1.96 * est.x.se
))
est.g.mi <- coefse['g','Estimate']
est.g.se <- coefse['g','Std.Error']
result <- append(result,
list(Bgy.est.amelia.full = est.g.mi,
Bgy.ci.upper.amelia.full = est.g.mi + 1.96 * est.g.se,
Bgy.ci.lower.amelia.full = est.g.mi - 1.96 * est.g.se
))
return(result)
}
run_simulation <- function(df, result){
accuracy <- df[,mean(w_pred==x)]
@ -48,19 +203,7 @@ run_simulation <- function(df, result){
Bgy.ci.lower.naive = naive.ci.Bgy[1]))
## multiple imputation when k is observed
## amelia does great at this one.
noms <- c()
if(length(unique(df$x.obs)) <=2){
noms <- c(noms, 'x.obs')
}
if(length(unique(df$g)) <=2){
noms <- c(noms, 'g')
}
amelia.out.k <- amelia(df, m=200, p2s=0, idvars=c('x','w_pred'),noms=noms)
amelia.out.k <- amelia(df, m=200, p2s=0, idvars=c('x','w_pred'))
mod.amelia.k <- zelig(y~x.obs+g, model='ls', data=amelia.out.k$imputations, cite=FALSE)
(coefse <- combine_coef_se(mod.amelia.k, messages=FALSE))