diff --git a/NEWS.md b/NEWS.md
index e001d5ab..4aa50774 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -14,14 +14,14 @@ unique url.
 ### Some of the new plots and features in ShinyStan app 
 * Rebranding (new look to reflect changes to Stan logo and website)
 * HMC/NUTS diagnostic plots ('Diagnose' page, 'HMC/NUTS (plots)' tab)
-* Specify arbitrary transformations (e.g. log, logit, sqrt, etc.) for density, 
+* Specify transformations (e.g. log, logit, sqrt, etc.) for density, 
 histogram, bivariate, trivariate plots (on 'Explore' page) and HMC/NUTS diagnostics
 plots.
-* Bivariate scatterplot plot also shows divergent iterations and max treedepth 
+* Many plots can now also be saved as pdf
+* Bivariate scatterplot plot also shows divergent transitions and max treedepth 
 saturation (on 'Explore' page)
 * (Experimental) Introduce basic graphical posterior predictive 
 checking ('Diagnose' page, 'PPcheck' tab) for limited class of models
-* Option to show partial autocorrelations 
-('Diagnose' page, 'Autocorrelation' tab)
+* Option to show partial autocorrelations ('Diagnose' page, 'Autocorrelation' tab)
 * Better customization of of posterior summary statistics table
 * Many improvements to GUI design
diff --git a/R/convenience.R b/R/convenience.R
index 670b2735..36fb9a3c 100644
--- a/R/convenience.R
+++ b/R/convenience.R
@@ -65,11 +65,12 @@ retrieve_sd <- function(sso, pars) {
 
 
 sp_check <- function(sso) {
-  if (is.na(sso@sampler_params[[1]])) stop("Only available for Stan models.")
+  if (identical(sso@sampler_params, list(NA)))
+    stop("No sampler parameters found", call. = FALSE)
 }
 
 retrieve_max_treedepth <- function(sso, inc_warmup = FALSE) {
-  sp_check()
+  sp_check(sso)
   rows <- if (inc_warmup) 1:sso@nIter else (sso@nWarmup+1):sso@nIter
   max_td <- sapply(sso@sampler_params,
                    function(x) max(x[rows,"treedepth__"]))
@@ -78,7 +79,7 @@ retrieve_max_treedepth <- function(sso, inc_warmup = FALSE) {
 }
 
 retrieve_prop_divergent <- function(sso, inc_warmup = FALSE) {
-  sp_check()
+  sp_check(sso)
   rows <- if (inc_warmup) 1:sso@nIter else (sso@nWarmup+1):sso@nIter
   prop_div <- sapply(sso@sampler_params,
                      function(x) mean(x[rows,"n_divergent__"]))
@@ -87,7 +88,7 @@ retrieve_prop_divergent <- function(sso, inc_warmup = FALSE) {
 }
 
 retrieve_avg_stepsize <- function(sso, inc_warmup = FALSE) {
-  sp_check()
+  sp_check(sso)
   rows <- if (inc_warmup) 1:sso@nIter else (sso@nWarmup+1):sso@nIter
   avg_ss <- sapply(sso@sampler_params,
                    function(x) mean(x[rows,"stepsize__"]))
@@ -96,7 +97,7 @@ retrieve_avg_stepsize <- function(sso, inc_warmup = FALSE) {
 }
 
 retrieve_avg_accept <- function(sso, inc_warmup = FALSE) {
-  sp_check()
+  sp_check(sso)
   rows <- if (inc_warmup) 1:sso@nIter else (sso@nWarmup+1):sso@nIter
   avg_accept <- sapply(sso@sampler_params,
                        function(x) mean(x[rows,"accept_stat__"]))
diff --git a/R/misc.R b/R/misc.R
index 276f9bde..5cf87455 100644
--- a/R/misc.R
+++ b/R/misc.R
@@ -126,3 +126,38 @@ set_ppcheck_defaults <- function(appDir, yrep_name, y_name = "y") {
   )
 }
 
+.retrieve <- function(sso, what, ...) {
+  if (what %in% c("rhat", "rhats", "Rhat", "Rhats", "r_hat", "R_hat")) {
+    return(retrieve_rhat(sso, ...))
+  }
+  if (what %in% c("N_eff","n_eff", "neff", "Neff", "ess","ESS")) {
+    return(retrieve_neff(sso, ...))
+  }
+  if (grepl_ic("mean", what)) {
+    return(retrieve_mean(sso, ...))
+  }
+  if (grepl_ic("sd", what)) {
+    return(retrieve_sd(sso, ...))
+  }
+  if (what %in% c("se_mean", "mcse")) {
+    return(retrieve_mcse(sso, ...))
+  }
+  if (grepl_ic("quant", what)) {
+    return(retrieve_quant(sso, ...))
+  }
+  if (grepl_ic("median", what)) {
+    return(retrieve_median(sso, ...))
+  }
+  if (grepl_ic("tree", what) | grepl_ic("depth", what)) {
+    return(retrieve_max_treedepth(sso, ...))
+  }
+  if (grepl_ic("step", what)) {
+    return(retrieve_avg_stepsize(sso, ...))
+  }
+  if (grepl_ic("diverg", what)) {
+    return(retrieve_prop_divergent(sso, ...))
+  }
+  if (grepl_ic("accept", what)) {
+    return(retrieve_avg_accept(sso, ...))
+  }
+}
\ No newline at end of file
diff --git a/R/retrieve.R b/R/retrieve.R
index dac4ebd4..b5e94a09 100644
--- a/R/retrieve.R
+++ b/R/retrieve.R
@@ -62,38 +62,5 @@
 
 retrieve <- function(sso, what, ...) {
   sso_check(sso)
-
-  if (what %in% c("rhat", "rhats", "Rhat", "Rhats", "r_hat", "R_hat")) {
-    return(retrieve_rhat(sso, ...))
-  }
-  if (what %in% c("N_eff","n_eff", "neff", "Neff", "ess","ESS")) {
-    return(retrieve_neff(sso, ...))
-  }
-  if (grepl_ic("mean", what)) {
-    return(retrieve_mean(sso, ...))
-  }
-  if (grepl_ic("sd", what)) {
-    return(retrieve_sd(sso, ...))
-  }
-  if (what %in% c("se_mean", "mcse")) {
-    return(retrieve_mcse(sso, ...))
-  }
-  if (grepl_ic("quant", what)) {
-    return(retrieve_quant(sso, ...))
-  }
-  if (grepl_ic("median", what)) {
-    return(retrieve_median(sso, ...))
-  }
-  if (grepl_ic("tree", what) | grepl_ic("depth", what)) {
-    return(retrieve_max_treedepth(sso, ...))
-  }
-  if (grepl_ic("step", what)) {
-    return(retrieve_avg_stepsize(sso, ...))
-  }
-  if (grepl_ic("diverg", what)) {
-    return(retrieve_prop_divergent(sso, ...))
-  }
-  if (grepl_ic("accept", what)) {
-    return(retrieve_avg_accept(sso, ...))
-  }
+  .retrieve(sso, what, ...)
 }