knitr::opts_chunk$set(
collapse = TRUE,
comment = "#>",
fig.width = 8,
fig.height = 6,
warning = FALSE,
message = FALSE
)shrinkr is designed to work seamlessly with modern R workflows. This vignette shows practical examples of using shrinkr with:
Imagine a clinical trial run across 5 regions testing a new treatment. We have Stage 1 posterior samples from region-specific analyses.
set.seed(1104)
# True effects (unknown in practice)
true_effects <- c(0.45, 0.60, 0.38, -0.10, 0.65)
region_names <- c("North", "South", "East", "West", "Central")
# Simulate posterior samples from Stage 1
samples_list <- lapply(1:5, function(i) {
matrix(rnorm(2000, true_effects[i], 0.20), ncol = 1)
})
names(samples_list) <- region_names# Fit mixture approximation
mix <- fit_mixture(samples_list, K_max = 3, verbose = FALSE)
# Specify hierarchical priors
priors <- list(
mu = dist_normal(0, 5),
tau = dist_truncated(dist_student_t(3, 0, 1), lower = 0)
)
# Run hierarchical shrinkage
fit <- shrink(
mixture = mix,
hierarchical_priors = priors,
chains = 4,
iter = 2000,
warmup = 1000,
cores = 1,
seed = 2024,
refresh = 0
)
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#> Chain 4:The posterior package provides the foundation for working with MCMC draws.
# Extract all parameters as draws_df
draws <- as_draws_df(fit)
# See what's available
variables(draws)
#> [1] "mu" "tau" "theta[1]" "theta[2]" "theta[3]"
#> [6] "theta[4]" "theta[5]" "tau_squared" "lp__"
# Extract specific parameters
mu_tau_draws <- extract_mu_tau(fit)
theta_draws <- extract_theta(fit)# Quick summary of all parameters
summarize_draws(draws)
#> # A tibble: 9 × 10
#> variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
#> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 mu 0.398 0.395 0.182 0.155 1.11e-1 0.700 1.00 1597. 1394.
#> 2 tau 0.306 0.269 0.203 0.173 4.73e-2 0.687 1.00 1175. 1258.
#> 3 theta[1] 0.427 0.424 0.162 0.154 1.68e-1 0.704 1.00 5061. 3283.
#> 4 theta[2] 0.517 0.509 0.171 0.168 2.50e-1 0.811 1.00 4120. 3799.
#> 5 theta[3] 0.378 0.383 0.162 0.154 1.09e-1 0.639 1.00 5106. 3403.
#> 6 theta[4] 0.0997 0.108 0.211 0.219 -2.63e-1 0.430 1.00 2176. 2757.
#> 7 theta[5] 0.549 0.539 0.179 0.183 2.80e-1 0.856 1.00 3853. 3141.
#> 8 tau_squa… 0.135 0.0723 0.196 0.0816 2.23e-3 0.472 1.00 1175. 1258.
#> 9 lp__ -6.44 -6.11 3.01 2.95 -1.17e+1 -2.05 1.00 1240. 2011.
# Focus on theta parameters
summarize_draws(theta_draws, mean, sd, median, mad, ~quantile(.x, c(0.025, 0.975)))
#> # A tibble: 19 × 7
#> variable mean sd median mad `2.5%` `97.5%`
#> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 mu 0.398 0.182 0.395 0.155 0.0220 0.800
#> 2 tau 0.306 0.203 0.269 0.173 0.0255 0.806
#> 3 theta_c[1] 0.0282 0.987 0.0260 0.993 -1.89 1.99
#> 4 theta_c[2] 0.000676 1.02 -0.00862 1.02 -1.93 2.03
#> 5 theta_c[3] -0.0272 0.990 -0.0175 0.998 -1.96 1.90
#> 6 theta_c[4] -0.00466 0.980 -0.0140 0.971 -1.93 1.88
#> 7 theta_c[5] 0.0108 1.04 -0.00245 1.06 -1.97 2.09
#> 8 z[1] 0.108 0.748 0.103 0.711 -1.37 1.63
#> 9 z[2] 0.421 0.727 0.404 0.701 -1.01 1.88
#> 10 z[3] -0.0531 0.711 -0.0742 0.673 -1.46 1.41
#> 11 z[4] -1.02 0.783 -1.02 0.770 -2.55 0.518
#> 12 z[5] 0.524 0.753 0.508 0.730 -0.962 2.02
#> 13 theta[1] 0.427 0.162 0.424 0.154 0.118 0.771
#> 14 theta[2] 0.517 0.171 0.509 0.168 0.204 0.872
#> 15 theta[3] 0.378 0.162 0.383 0.154 0.0491 0.696
#> 16 theta[4] 0.0997 0.211 0.108 0.219 -0.334 0.473
#> 17 theta[5] 0.549 0.179 0.539 0.183 0.230 0.918
#> 18 tau_squared 0.135 0.196 0.0723 0.0816 0.000649 0.649
#> 19 lp__ -6.44 3.01 -6.11 2.95 -13.1 -1.45
# Convergence diagnostics
summarize_draws(draws, default_convergence_measures())
#> # A tibble: 9 × 4
#> variable rhat ess_bulk ess_tail
#> <chr> <dbl> <dbl> <dbl>
#> 1 mu 1.00 1597. 1394.
#> 2 tau 1.00 1175. 1258.
#> 3 theta[1] 1.00 5061. 3283.
#> 4 theta[2] 1.00 4120. 3799.
#> 5 theta[3] 1.00 5106. 3403.
#> 6 theta[4] 1.00 2176. 2757.
#> 7 theta[5] 1.00 3853. 3141.
#> 8 tau_squared 1.00 1175. 1258.
#> 9 lp__ 1.00 1240. 2011.
# Custom summaries
summarise_draws(
theta_draws,
mean,
sd,
prob_positive = ~mean(.x > 0),
prob_large = ~mean(.x > 0.5)
)
#> # A tibble: 19 × 5
#> variable mean sd prob_positive prob_large
#> <chr> <dbl> <dbl> <dbl> <dbl>
#> 1 mu 0.398 0.182 0.980 0.247
#> 2 tau 0.306 0.203 1 0.145
#> 3 theta_c[1] 0.0282 0.987 0.513 0.313
#> 4 theta_c[2] 0.000676 1.02 0.494 0.309
#> 5 theta_c[3] -0.0272 0.990 0.491 0.298
#> 6 theta_c[4] -0.00466 0.980 0.494 0.298
#> 7 theta_c[5] 0.0108 1.04 0.498 0.323
#> 8 z[1] 0.108 0.748 0.560 0.286
#> 9 z[2] 0.421 0.727 0.724 0.448
#> 10 z[3] -0.0531 0.711 0.457 0.208
#> 11 z[4] -1.02 0.783 0.0855 0.026
#> 12 z[5] 0.524 0.753 0.764 0.503
#> 13 theta[1] 0.427 0.162 0.995 0.306
#> 14 theta[2] 0.517 0.171 1.000 0.518
#> 15 theta[3] 0.378 0.162 0.988 0.212
#> 16 theta[4] 0.0997 0.211 0.688 0.0138
#> 17 theta[5] 0.549 0.179 1.000 0.580
#> 18 tau_squared 0.135 0.196 1 0.0435
#> 19 lp__ -6.44 3.01 0.001 0.00025# Check Rhat for all parameters
all_rhats <- summarise_draws(draws, "rhat")
max(all_rhats$rhat, na.rm = TRUE)
#> [1] 1.001981
# Check effective sample size
summarise_draws(draws, "ess_bulk", "ess_tail") %>%
filter(ess_bulk < 400 | ess_tail < 400)
#> # A tibble: 0 × 3
#> # ℹ 3 variables: variable <chr>, ess_bulk <dbl>, ess_tail <dbl>
# Detailed diagnostics for specific parameters
summarise_draws(
subset_draws(draws, variable = c("mu", "tau")),
default_convergence_measures()
)
#> # A tibble: 2 × 4
#> variable rhat ess_bulk ess_tail
#> <chr> <dbl> <dbl> <dbl>
#> 1 mu 1.00 1597. 1394.
#> 2 tau 1.00 1175. 1258.bayesplot provides essential MCMC diagnostic visualizations.
Check for mixing and stationarity:
Compare chains and check for multimodality:
Visualize posterior uncertainties:
# All thetas with 50% and 95% intervals
mcmc_intervals(draws, regex_pars = "theta", prob = 0.5, prob_outer = 0.95)
# With point estimates
mcmc_intervals_data(draws, regex_pars = "theta") %>%
ggplot(aes(y = parameter)) +
geom_pointrange(aes(x = m, xmin = ll, xmax = hh)) +
geom_point(aes(x = m), size = 3) +
labs(title = "Posterior Intervals for Regional Effects", x = "Effect Size", y = NULL)tidybayes makes it easy to manipulate and visualize posteriors using tidy principles.
# Gather theta parameters into long format
theta_tidy <- draws %>%
gather_draws(theta[region]) %>%
mutate(region = region_names[region])
head(theta_tidy)
#> # A tibble: 6 × 6
#> # Groups: region, .variable [1]
#> region .chain .iteration .draw .variable .value
#> <chr> <int> <int> <int> <chr> <dbl>
#> 1 North 1 1 1 theta 0.596
#> 2 North 1 2 2 theta 0.527
#> 3 North 1 3 3 theta 0.526
#> 4 North 1 4 4 theta 0.355
#> 5 North 1 5 5 theta 0.467
#> 6 North 1 6 6 theta 0.386
# Spread into wide format
theta_wide <- draws %>%
spread_draws(theta[region]) %>%
mutate(region = region_names[region])
head(theta_wide)
#> # A tibble: 6 × 5
#> # Groups: region [1]
#> region theta .chain .iteration .draw
#> <chr> <dbl> <int> <int> <int>
#> 1 North 0.596 1 1 1
#> 2 North 0.527 1 2 2
#> 3 North 0.526 1 3 3
#> 4 North 0.355 1 4 4
#> 5 North 0.467 1 5 5
#> 6 North 0.386 1 6 6# Median and 95% quantile intervals
theta_tidy %>%
group_by(region) %>%
median_qi(.value, .width = 0.95)
#> # A tibble: 5 × 7
#> region .value .lower .upper .width .point .interval
#> <chr> <dbl> <dbl> <dbl> <dbl> <chr> <chr>
#> 1 Central 0.539 0.230 0.918 0.95 median qi
#> 2 East 0.383 0.0491 0.696 0.95 median qi
#> 3 North 0.424 0.118 0.771 0.95 median qi
#> 4 South 0.509 0.204 0.872 0.95 median qi
#> 5 West 0.108 -0.334 0.473 0.95 median qi
# Multiple interval widths
theta_tidy %>%
group_by(region) %>%
median_qi(.value, .width = c(0.5, 0.8, 0.95))
#> # A tibble: 15 × 7
#> region .value .lower .upper .width .point .interval
#> <chr> <dbl> <dbl> <dbl> <dbl> <chr> <chr>
#> 1 Central 0.539 0.419 0.668 0.5 median qi
#> 2 East 0.383 0.273 0.482 0.5 median qi
#> 3 North 0.424 0.320 0.527 0.5 median qi
#> 4 South 0.509 0.399 0.626 0.5 median qi
#> 5 West 0.108 -0.0406 0.254 0.5 median qi
#> 6 Central 0.539 0.332 0.788 0.8 median qi
#> 7 East 0.383 0.174 0.574 0.8 median qi
#> 8 North 0.424 0.227 0.630 0.8 median qi
#> 9 South 0.509 0.304 0.744 0.8 median qi
#> 10 West 0.108 -0.179 0.374 0.8 median qi
#> 11 Central 0.539 0.230 0.918 0.95 median qi
#> 12 East 0.383 0.0491 0.696 0.95 median qi
#> 13 North 0.424 0.118 0.771 0.95 median qi
#> 14 South 0.509 0.204 0.872 0.95 median qi
#> 15 West 0.108 -0.334 0.473 0.95 median qi
# Mean and HDI (highest density interval)
theta_tidy %>%
group_by(region) %>%
mean_hdi(.value, .width = 0.95)
#> # A tibble: 5 × 7
#> region .value .lower .upper .width .point .interval
#> <chr> <dbl> <dbl> <dbl> <dbl> <chr> <chr>
#> 1 Central 0.549 0.198 0.881 0.95 mean hdi
#> 2 East 0.378 0.0620 0.706 0.95 mean hdi
#> 3 North 0.427 0.118 0.771 0.95 mean hdi
#> 4 South 0.517 0.194 0.856 0.95 mean hdi
#> 5 West 0.0997 -0.295 0.502 0.95 mean hdi# Probability of positive effect
theta_tidy %>%
group_by(region) %>%
summarise(
mean_effect = mean(.value),
sd_effect = sd(.value),
prob_positive = mean(.value > 0),
prob_clinically_meaningful = mean(.value > 0.3),
.groups = "drop"
) %>%
arrange(desc(prob_positive))
#> # A tibble: 5 × 5
#> region mean_effect sd_effect prob_positive prob_clinically_meaningful
#> <chr> <dbl> <dbl> <dbl> <dbl>
#> 1 Central 0.549 0.179 1.000 0.934
#> 2 South 0.517 0.171 1.000 0.904
#> 3 North 0.427 0.162 0.995 0.787
#> 4 East 0.378 0.162 0.988 0.699
#> 5 West 0.0997 0.211 0.688 0.182# Method 1: Using shrinkr's built-in function
L <- rbind(
"South - North" = c(-1, 1, 0, 0, 0),
"Central - North" = c(-1, 0, 0, 0, 1),
"South - West" = c(0, 1, 0, -1, 0)
)
contrasts <- theta_contrasts(fit, L, labels = rownames(L))
summarise_draws(contrasts)
#> # A tibble: 3 × 10
#> variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
#> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 South - North 0.0904 0.0715 0.219 0.198 -0.251 0.460 1.00 5281. 3574.
#> 2 Central - No… 0.123 0.102 0.226 0.216 -0.226 0.505 1.00 5179. 3583.
#> 3 South - West 0.417 0.404 0.289 0.312 -0.00425 0.923 1.00 2129. 2363.
# Method 2: Using tidybayes compare_levels
theta_wide %>%
compare_levels(theta, by = region, comparison = "pairwise") %>%
group_by(region) %>%
median_qi(theta) %>%
arrange(desc(theta))
#> # A tibble: 10 × 7
#> region theta .lower .upper .width .point .interval
#> <chr> <dbl> <dbl> <dbl> <dbl> <chr> <chr>
#> 1 South - East 0.119 -0.283 0.615 0.95 median qi
#> 2 South - North 0.0715 -0.334 0.550 0.95 median qi
#> 3 North - East 0.0336 -0.366 0.501 0.95 median qi
#> 4 South - Central -0.0211 -0.481 0.398 0.95 median qi
#> 5 North - Central -0.102 -0.593 0.302 0.95 median qi
#> 6 East - Central -0.151 -0.670 0.241 0.95 median qi
#> 7 West - East -0.257 -0.797 0.135 0.95 median qi
#> 8 West - North -0.306 -0.907 0.0952 0.95 median qi
#> 9 West - South -0.404 -1.03 0.0373 0.95 median qi
#> 10 West - Central -0.437 -1.07 0.0277 0.95 median qiggdist provides publication-ready distribution visualizations.
Eye + interval visualization:
theta_tidy %>%
ggplot(aes(y = region, x = .value)) +
stat_halfeye(
.width = c(0.66, 0.95),
fill = "steelblue"
) +
geom_vline(xintercept = 0, linetype = "dashed", alpha = 0.5) +
labs(
title = "Regional Treatment Effects",
subtitle = "Posterior distributions with median and 66%/95% intervals",
x = "Treatment Effect",
y = NULL
)Density with separate interval layer:
theta_tidy %>%
ggplot(aes(y = region, x = .value)) +
stat_slab(aes(fill_ramp = after_stat(level)), fill = "steelblue", alpha = 0.8) +
stat_pointinterval(.width = c(0.66, 0.95), position = position_nudge(y = -0.15)) +
scale_fill_ramp_discrete(range = c(1, 0.2), guide = "none") +
labs(
title = "Posterior Densities with Quantile Intervals",
x = "Treatment Effect",
y = NULL
)Each dot = quantile of the distribution:
theta_tidy %>%
ggplot(aes(y = region, x = .value)) +
stat_dots(quantiles = 100) +
geom_vline(xintercept = 0, linetype = "dashed", alpha = 0.5) +
labs(
title = "Quantile Dotplots",
subtitle = "Each dot represents 1% of the posterior",
x = "Treatment Effect",
y = NULL
)Continuous representation of uncertainty:
theta_tidy %>%
ggplot(aes(y = region, x = .value)) +
stat_gradientinterval(.width = ppoints(50)) +
scale_color_brewer(palette = "Blues", guide = "none") +
labs(
title = "Gradient Interval Representation",
x = "Treatment Effect",
y = NULL
)# Get pre-shrunk estimates from mixture
pre_shrunk <- summarise_theta(fit) %>%
mutate(type = "Pre-shrunk")
# Get post-shrunk estimates
post_shrunk <- summarise_theta(fit) %>%
mutate(type = "Post-shrunk")
# Or use shrinkr's built-in plot
plot(fit, group_names = region_names)# Get the hierarchical mean (mu)
mu_draws <- draws %>% spread_draws(mu)
mu_mean <- mean(mu_draws$mu)
# Combine with Stage 1 samples
stage1_draws <- lapply(seq_along(samples_list), function(i) {
data.frame(
region = region_names[i],
.value = samples_list[[i]][,1],
type = "Stage 1"
)
}) %>% bind_rows()
stage2_draws <- theta_tidy %>%
mutate(type = "Stage 2 (Shrunk)")
# Plot side by side
bind_rows(stage1_draws, stage2_draws) %>%
ggplot(aes(y = region, x = .value, fill = type)) +
stat_halfeye(alpha = 0.7, position = position_dodge(width = 0.4)) +
geom_vline(xintercept = 0, linetype = "dashed", alpha = 0.5, color = "gray50") +
geom_vline(xintercept = mu_mean, linetype = "solid", alpha = 0.8,
color = "darkred", linewidth = 1) +
annotate("text", x = mu_mean, y = 0.5,
label = sprintf("Global mean (μ) = %.2f", mu_mean),
hjust = -0.1, color = "darkred", size = 3.5) +
scale_fill_manual(values = c("Stage 1" = "gray70", "Stage 2 (Shrunk)" = "steelblue")) +
labs(
title = "Stage 1 vs Stage 2: Effect of Hierarchical Shrinkage",
subtitle = "Stage 2 estimates are pulled toward the global mean",
x = "Treatment Effect",
y = NULL,
fill = NULL
) +
theme(legend.position = "bottom")Here’s a typical analysis workflow using tidy principles:
# 1. Extract and prepare data
analysis_data <- draws %>%
spread_draws(mu, tau, theta[i]) %>%
mutate(region = region_names[i])
# 2. Compute summaries
summary_table <- analysis_data %>%
group_by(region) %>%
summarise(
mean = mean(theta),
median = median(theta),
sd = sd(theta),
q025 = quantile(theta, 0.025),
q975 = quantile(theta, 0.975),
prob_positive = mean(theta > 0),
prob_clinically_important = mean(theta > 0.3),
.groups = "drop"
) %>%
arrange(desc(median))
print(summary_table)
#> # A tibble: 5 × 8
#> region mean median sd q025 q975 prob_positive prob_clinically_impo…¹
#> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 Central 0.549 0.539 0.179 0.230 0.918 1.000 0.934
#> 2 South 0.517 0.509 0.171 0.204 0.872 1.000 0.904
#> 3 North 0.427 0.424 0.162 0.118 0.771 0.995 0.787
#> 4 East 0.378 0.383 0.162 0.0491 0.696 0.988 0.699
#> 5 West 0.0997 0.108 0.211 -0.334 0.473 0.688 0.182
#> # ℹ abbreviated name: ¹prob_clinically_important
# 3. Create advanced figure
library(patchwork)
p1 <- analysis_data %>%
ggplot(aes(y = reorder(region, theta), x = theta)) +
stat_halfeye(.width = c(0.66, 0.95), fill = "steelblue") +
geom_vline(xintercept = 0, linetype = "dashed", alpha = 0.5) +
labs(
title = "A. Regional Treatment Effects",
x = "Effect Size",
y = NULL
)
p2 <- analysis_data %>%
dplyr::ungroup() %>%
dplyr::select(mu, tau, .draw) %>%
dplyr::distinct() %>%
tidyr::pivot_longer(cols = c(mu, tau), names_to = "name", values_to = "value") %>%
ggplot(aes(x = value, fill = name)) +
stat_halfeye(alpha = 0.7) +
facet_wrap(~name, scales = "free", labeller = label_both) +
scale_fill_brewer(palette = "Set2") +
labs(
title = "B. Hyperparameters",
x = "Value",
y = "Density"
) +
theme(legend.position = "none")
p3 <- analysis_data %>%
dplyr::ungroup() %>%
dplyr::select(.draw, region, theta) %>%
compare_levels(theta, by = region) %>%
ggplot(aes(y = region, x = theta)) +
stat_halfeye(fill = "coral", alpha = 0.7) +
geom_vline(xintercept = 0, linetype = "dashed", color = "red", alpha = 0.5) +
labs(
title = "C. Pairwise Regional Comparisons",
x = "Difference in Effect Size",
y = NULL
)
p4 <- analysis_data %>%
dplyr::ungroup() %>%
dplyr::select(.draw, mu, tau) %>%
dplyr::distinct() %>%
ggplot(aes(x = mu, y = tau)) +
geom_hex(bins = 30) +
stat_ellipse(level = 0.95, color = "red", linewidth = 1) +
scale_fill_viridis_c() +
labs(
title = "D. Hyperparameter Correlation",
x = expression(mu~"(global mean)"),
y = expression(tau~"(heterogeneity)")
)
(p1 + p2) / (p3 + p4) +
plot_annotation(
title = "Complete Bayesian Shrinkage Analysis",
subtitle = sprintf(
"Global effect: %.2f [%.2f, %.2f] | Heterogeneity (tau): %.2f",
median(analysis_data$mu),
quantile(analysis_data$mu, 0.025),
quantile(analysis_data$mu, 0.975),
median(analysis_data$tau)
)
)# Which region is best?
analysis_data %>%
group_by(.draw) %>%
slice_max(theta, n = 1) %>%
ungroup() %>%
count(region) %>%
mutate(probability = n / sum(n)) %>%
arrange(desc(probability))
#> # A tibble: 5 × 3
#> region n probability
#> <chr> <int> <dbl>
#> 1 Central 1679 0.420
#> 2 South 1260 0.315
#> 3 North 625 0.156
#> 4 East 395 0.0988
#> 5 West 41 0.0102
# Alternative: probability each region is best
analysis_data %>%
group_by(.draw) %>%
mutate(rank = rank(-theta)) %>%
ungroup() %>%
group_by(region) %>%
summarise(
prob_best = mean(rank == 1),
prob_top2 = mean(rank <= 2),
mean_rank = mean(rank),
.groups = "drop"
) %>%
arrange(mean_rank)
#> # A tibble: 5 × 4
#> region prob_best prob_top2 mean_rank
#> <chr> <dbl> <dbl> <dbl>
#> 1 Central 0.420 0.709 2.02
#> 2 South 0.315 0.630 2.23
#> 3 North 0.156 0.372 2.87
#> 4 East 0.0988 0.254 3.20
#> 5 West 0.0102 0.0357 4.67
# Pairwise comparisons: Probability that South > North
# Create wide format for comparisons
theta_wide_for_contrasts <- analysis_data %>%
ungroup() %>%
dplyr::select(.draw, region, theta) %>%
tidyr::pivot_wider(names_from = region, values_from = theta)
theta_wide_for_contrasts %>%
summarise(
prob_south_beats_north = mean(South > North),
prob_south_beats_north_by_02 = mean((South - North) > 0.2),
prob_central_beats_all = mean(
Central > North & Central > South &
Central > East & Central > West
)
)
#> # A tibble: 1 × 3
#> prob_south_beats_north prob_south_beats_north_by_02 prob_central_beats_all
#> <dbl> <dbl> <dbl>
#> 1 0.657 0.289 0.420# Classify effects into categories
theta_tidy %>%
group_by(region) %>%
summarise(
prob_harm = mean(.value < -0.1),
prob_null = mean(abs(.value) < 0.1),
prob_small_benefit = mean(.value > 0.1 & .value < 0.3),
prob_large_benefit = mean(.value > 0.3),
.groups = "drop"
) %>%
arrange(desc(prob_large_benefit))
#> # A tibble: 5 × 5
#> region prob_harm prob_null prob_small_benefit prob_large_benefit
#> <chr> <dbl> <dbl> <dbl> <dbl>
#> 1 Central 0 0.00325 0.0632 0.934
#> 2 South 0 0.003 0.0932 0.904
#> 3 North 0.001 0.019 0.193 0.787
#> 4 East 0.00325 0.043 0.254 0.699
#> 5 West 0.170 0.316 0.331 0.182
# Visualize classification
theta_tidy %>%
mutate(
category = case_when(
.value < -0.1 ~ "Harm",
abs(.value) < 0.1 ~ "Null",
.value > 0.1 & .value < 0.3 ~ "Small Benefit",
.value > 0.3 ~ "Large Benefit"
)
) %>%
count(region, category) %>%
group_by(region) %>%
mutate(probability = n / sum(n)) %>%
ggplot(aes(x = probability, y = region, fill = category)) +
geom_col(position = "stack") +
scale_fill_manual(
values = c(
"Harm" = "red",
"Null" = "gray",
"Small Benefit" = "lightblue",
"Large Benefit" = "darkblue"
)
) +
labs(
title = "Classification of Treatment Effects",
x = "Probability",
y = NULL,
fill = "Effect Category"
) +
theme(legend.position = "bottom")# Compute ranks for each draw
rank_data <- analysis_data %>%
group_by(.draw) %>%
mutate(rank = rank(-theta)) %>%
ungroup()
# Summary statistics
rank_summary <- rank_data %>%
group_by(region) %>%
summarise(
mean_rank = mean(rank),
median_rank = median(rank),
prob_rank1 = mean(rank == 1),
prob_rank2 = mean(rank == 2),
prob_top3 = mean(rank <= 3),
.groups = "drop"
) %>%
arrange(mean_rank)
print(rank_summary)
#> # A tibble: 5 × 6
#> region mean_rank median_rank prob_rank1 prob_rank2 prob_top3
#> <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 Central 2.02 2 0.420 0.289 0.874
#> 2 South 2.23 2 0.315 0.314 0.854
#> 3 North 2.87 3 0.156 0.216 0.662
#> 4 East 3.20 3 0.0988 0.155 0.53
#> 5 West 4.67 5 0.0102 0.0255 0.0788
# Visualize ranking distribution
rank_data %>%
ggplot(aes(x = rank, y = reorder(region, -theta))) +
stat_dots(quantiles = 100) +
scale_x_continuous(breaks = 1:5) +
labs(
title = "Ranking Distribution",
subtitle = "Each dot represents 1% of posterior draws",
x = "Rank (1 = best, 5 = worst)",
y = NULL
)
# Alternative: bar chart of ranking probabilities
rank_data %>%
count(region, rank) %>%
group_by(region) %>%
mutate(probability = n / sum(n)) %>%
ggplot(aes(x = rank, y = probability, fill = region)) +
geom_col() +
facet_wrap(~region, ncol = 1) +
scale_x_continuous(breaks = 1:5) +
scale_fill_brewer(palette = "Set2") +
labs(
title = "Probability of Each Rank by Region",
x = "Rank (1 = best)",
y = "Probability"
) +
theme(legend.position = "none")