## ----setup, include=FALSE-----------------------------------------------------
knitr::opts_chunk$set(echo = TRUE, fig.retina = 2)
# options(width = 80)
suppressPackageStartupMessages(library(dplyr))
suppressPackageStartupMessages(library(ggplot2))

## ----graphkey, fig.width = 7, fig.height = 5, echo = FALSE--------------------
library(dscore)
ib <- builtin_itembank |>
  filter(key == "gsed2406") |>
  mutate(
    a = get_age_equivalent(
      items = item,
      pct = 50,
      itembank = builtin_itembank
    )$a,
    a = a * 12
  ) |>
  select(a, instrument, label) |>
  na.omit()

ggplot(ib, aes(x = a, y = instrument, group = instrument)) +
  scale_y_discrete(limits = rev(unique(ib$instrument)), name = "") +
  scale_x_continuous(
    limits = c(0, 60),
    breaks = seq(0, 60, 12),
    name = "Age (months)"
  ) +
  geom_point(pch = 3, size = 1, colour = "blue") +
  theme_light() +
  theme(axis.text.y = element_text(hjust = 0, family = "mono"))

## ----getlabels----------------------------------------------------------------
library(dscore)
get_labels("by3cgd018")

## ----decompose_itemnames------------------------------------------------------
decompose_itemnames(c("by3cgd018", "denfmd014"))

## ----table--------------------------------------------------------------------
items <- get_itemnames()
din <- decompose_itemnames(items) |>
  dplyr::filter(!instrument %in% c("gsd", "gpa", "gto", "rap"))
knitr::kable(with(din, table(instrument, domain)), format = "html") |>
  kableExtra::column_spec(1, monospace = TRUE)

## ----ddigm--------------------------------------------------------------------
items <- head(get_itemnames(instrument = "mdt", domain = "gm"), 3)
get_labels(items)

## ----smalldataset-------------------------------------------------------------
data <- data.frame(
  id = c(1, 1, 2),
  age = c(1, 1.6, 0.9),
  mot1 = c(1, NA, NA),
  mot2 = c(0, 1, 1),
  mot3 = c(NA, 0, 1)
)
data

## ----rename-------------------------------------------------------------------
old_names <- names(data)[3:5]
new_names <- get_itemnames(instrument = "mdt", domain = "gm")[1:3]
names(data)[3:5] <- new_names
data

## ----milestones---------------------------------------------------------------
head(milestones[, c(1, 3, 4, 9:14)])

## -----------------------------------------------------------------------------
ds <- dscore(milestones, population = "dutch", key = "dutch")
dim(ds)

## -----------------------------------------------------------------------------
head(ds)

## ----bind---------------------------------------------------------------------
md <- cbind(milestones, ds)

## ----graphD, fig.width = 7, fig.height = 7------------------------------------
library(ggplot2)
library(dplyr)

# Prepare the reference ribbon data: sort by age and convert months → years
r <- builtin_references %>%
  filter(population == "dutch" & key == "dutch") %>%
  transmute(age_years = age, SDM2, SD0, SDP2) %>%
  arrange(age_years)

ggplot(md, aes(x = a, y = d, group = id, colour = sex)) +
  theme_light() +
  theme(
    legend.position = c(0.85, 0.15),
    legend.background = element_blank(),
    legend.key = element_blank()
  ) +
  geom_ribbon(
    data = r,
    inherit.aes = FALSE,
    aes(x = age_years, ymin = SDM2, ymax = SDP2),
    fill = "green",
    alpha = 0.1
  ) +
  geom_line(
    data = r,
    inherit.aes = FALSE,
    aes(x = age_years, y = SDM2),
    linewidth = 0.3,
    alpha = 0.6,
    colour = "green"
  ) +
  geom_line(
    data = r,
    inherit.aes = FALSE,
    aes(x = age_years, y = SDP2),
    linewidth = 0.3,
    alpha = 0.6,
    colour = "green"
  ) +
  geom_line(
    data = r,
    inherit.aes = FALSE,
    aes(x = age_years, y = SD0),
    linewidth = 0.5,
    alpha = 0.8,
    colour = "green"
  ) +
  coord_cartesian(xlim = c(0, 2.5)) +
  ylab(expression(italic(D) * "-score")) +
  xlab("Age (years)") +
  scale_color_brewer(palette = "Set1") +
  geom_line(linewidth = 0.1) +
  geom_point(size = 1)

## ----graphDAZ, fig.width = 7, fig.height = 5----------------------------------
ggplot(md, aes(x = a, y = daz, group = id, color = factor(sex))) +
  theme_light() +
  theme(legend.position = c(.85, .15)) +
  theme(legend.background = element_blank()) +
  theme(legend.key = element_blank()) +
  scale_color_brewer(palette = "Set1") +
  annotate(
    "rect",
    xmin = -Inf,
    xmax = Inf,
    ymin = -2,
    ymax = 2,
    alpha = 0.1,
    fill = "green"
  ) +
  coord_cartesian(
    xlim = c(0, 2.5),
    ylim = c(-4, 4)
  ) +
  geom_line(lwd = 0.1) +
  geom_point(size = 1) +
  xlab("Age (in years)") +
  ylab("DAZ")

## ----density, fig.width = 7, fig.height = 4-----------------------------------
ggplot(md) +
  theme_light() +
  scale_fill_brewer(palette = "Set1") +
  geom_density(
    aes(x = daz, group = sex, fill = sex),
    alpha = 0.4,
    adjust = 1.5,
    color = "transparent"
  ) +
  xlab("DAZ")

## ----independence-------------------------------------------------------------
summary(lm(daz ~ age * sex, data = md))

## ----multilevel---------------------------------------------------------------
library(Matrix)
library(lme4, quiet = TRUE)
lmer(daz ~ 1 + age + sex + sex * age + (1 + age | id), data = md)