Run JAGS model and get posterior point estimates with
uncertainty
mod <- run_jags_model(jagsdata = pkg_data, jagsparams = NULL,
n_iter = 50, n_burnin = 1, n_thin = 2)
# n_iter = 50000, n_burnin = 10000, n_thin = 20)
Check the model diagnostics
We use this to evaluate the convergence of the model parameters. We
should expect to see R-hat values of approximately 1.05. The plot
function will give you a visual summary for each parameter
monitored.
plot(mod$JAGS)
print(mod$JAGS)
Using the ggplot2 and tidybayes R packages, we will check the trace
plots to assess the convergence of individual parameters. We expect to
see a ‘caterpillar’ like appearance of the chains over the
iterations.
sample_draws <- tidybayes::tidy_draws(mod$JAGS$BUGSoutput$sims.matrix)
var <- sample_draws %>% dplyr::select(.chain, .iteration, .draw,`P[1,2,1]`) %>%
dplyr::mutate(chain = rep(1:2, each=mod$JAGS$BUGSoutput$n.keep)) %>%
dplyr::mutate(iteration = rep(1:mod$JAGS$BUGSoutput$n.keep, 2))
ggplot2::ggplot(data=var) +
ggplot2::geom_line(ggplot2::aes(x=iteration, y=`P[1,2,1]`, color=as.factor(chain)))
Plot posterior point estimates with uncertainty
plots <- plot_estimates(jagsdata = pkg_data, model_output = mod)
plots[[1]]
Review the complete posterior sample of estimated method-supply
shares
This function will allow you to pull out the posterior sample of
estimated method supply shares. The posterior sample will be of size
‘nposterior’. Note that ‘nposterior’ should not be larger than your
total iterations (given in ‘run_jags_model’) In this example, we supply
the JAGS model object and the JAGS input data to the function, we set
‘nposterior=4’ to pull out 4 posterior samples.
post_samps <- get_posterior_P_samps(jagsdata = pkg_data, model_output = mod, nposterior=4)
head(post_samps)