## ----diag-setup, message=FALSE, warning=FALSE---------------------------------
library(gtregression)
library(dplyr)

data("data_birthwt", package = "gtregression")

birthwt_data <- data_birthwt |>
  mutate(
    race = factor(race, levels = c(1, 2, 3),
                  labels = c("White", "Black", "Other")),
    smoke = factor(smoke, levels = c(0, 1), labels = c("No", "Yes")),
    ht = factor(ht, levels = c(0, 1), labels = c("No", "Yes")),
    ui = factor(ui, levels = c(0, 1), labels = c("No", "Yes")),
    low = factor(low, levels = c(0, 1), labels = c("Normal BW", "Low BW")),
    ptl_cat = factor(ifelse(ptl > 0, "Yes", "No"), levels = c("No", "Yes"))
  )

exposures <- c("age", "lwt", "race", "smoke", "ht", "ui", "ptl_cat")

## ----diag-convergence, message=FALSE, warning=FALSE---------------------------
check_convergence(
  data = birthwt_data,
  exposures = exposures,
  outcome = low,
  approach = logit,
  multivariate = TRUE
)

## ----diag-convergence-logbin, message=FALSE, warning=FALSE--------------------
check_convergence(
  data = birthwt_data,
  exposures = c("smoke", "ht", "ui", "ptl_cat"),
  outcome = low,
  approach = logbinomial,
  multivariate = TRUE
)

## ----diag-collinearity, message=FALSE, warning=FALSE--------------------------
birthwt_multi <- multi_reg(
  data = birthwt_data,
  outcome = low,
  exposures = exposures,
  approach = logit
)

check_collinearity(birthwt_multi, format = gt)

## ----diag-collinearity-adjusted, message=FALSE, warning=FALSE-----------------
birthwt_adjusted <- multi_reg(
  data = birthwt_data,
  outcome = low,
  exposures = c("smoke", "ht", "ui", "ptl_cat"),
  adjust_for = c("age", "lwt", "race"),
  approach = logit
)

check_collinearity(birthwt_adjusted, format = tibble)

## ----diag-fit-logistic, message=FALSE, warning=FALSE--------------------------
plot_model_fit(
  birthwt_multi,
  type = calibration,
  bins = 6
)

## ----diag-fit-uni, message=FALSE, warning=FALSE-------------------------------
birthwt_uni <- uni_reg(
  data = birthwt_data,
  outcome = low,
  exposures = c("age", "lwt", "smoke"),
  approach = logit
)

plot_model_fit(
  birthwt_uni,
  model_name = smoke,
  type = residual
)

## ----diag-fit-linear, message=FALSE, warning=FALSE----------------------------
fit_lm <- lm(bwt ~ age + lwt, data = birthwt_data)
plot_model_fit(fit_lm)

## ----diag-ph-setup, message=FALSE, warning=FALSE------------------------------
data("data_lungcancer", package = "gtregression")

lung_data <- data_lungcancer |>
  mutate(
    trt = factor(trt, levels = c(1, 2),
                 labels = c("Standard treatment", "Test treatment")),
    prior = factor(prior, levels = c(0, 10), labels = c("No", "Yes")),
    celltype = factor(
      celltype,
      levels = c("squamous", "smallcell", "adeno", "large"),
      labels = c("Squamous", "Small cell", "Adenocarcinoma", "Large cell")
    )
  )

cox_fit <- cox_reg(
  data = lung_data,
  time = time,
  event = status,
  exposures = c(trt, celltype, prior),
  adjust_for = c(age, karno)
)

## ----diag-ph-table, message=FALSE, warning=FALSE------------------------------
check_ph(cox_fit, format = gt)

## ----diag-ph-tibble, message=FALSE, warning=FALSE-----------------------------
check_ph(cox_fit, transform = rank, format = tibble)

## ----diag-compare-logit, message=FALSE, warning=FALSE-------------------------
logit_m0 <- multi_reg(
  data = birthwt_data,
  outcome = low,
  exposures = smoke,
  approach = logit
)

logit_m1 <- multi_reg(
  data = birthwt_data,
  outcome = low,
  exposures = c(smoke, age, lwt),
  approach = logit
)

logit_m2 <- multi_reg(
  data = birthwt_data,
  outcome = low,
  exposures = c(smoke, age, lwt, race, ht, ui),
  approach = logit
)

logit_model_comparison <- compare_models(
  logit_m0,
  logit_m1,
  logit_m2,
  model_names = c(
    "Smoking only",
    "Add age and weight",
    "Full clinical model"
  ),
  primary_exposure = smoke,
  format = gt
)

logit_model_comparison$table

## ----diag-compare-cox, message=FALSE, warning=FALSE---------------------------
cox_m0 <- cox_reg(
  data = lung_data,
  time = time,
  event = status,
  exposures = trt
)

cox_m1 <- cox_reg(
  data = lung_data,
  time = time,
  event = status,
  exposures = trt,
  adjust_for = c(age, karno)
)

cox_m2 <- cox_reg(
  data = lung_data,
  time = time,
  event = status,
  exposures = c(trt, age, karno, celltype, prior),
  multivariable = TRUE
)

cox_model_comparison <- compare_models(
  list(
    "Treatment only" = cox_m0,
    "Add age and performance" = cox_m1,
    "Full clinical model" = cox_m2
  ),
  primary_exposure = trt,
  format = gt
)

cox_model_comparison$table

## ----diag-select, message=FALSE, warning=FALSE--------------------------------
selected <- select_models(
  data = birthwt_data,
  outcome = low,
  exposures = exposures,
  approach = logit,
  direction = forward
)

selected

## ----diag-select-other-directions, message=FALSE, warning=FALSE---------------
select_models(
  data = birthwt_data,
  outcome = low,
  exposures = exposures,
  approach = logit,
  direction = backward,
  format = tibble
)$results_table

select_models(
  data = birthwt_data,
  outcome = low,
  exposures = exposures,
  approach = logit,
  direction = both,
  format = tibble
)$results_table