diff --git a/R/meta_run.R b/R/meta_run.R
index 8ff3f6b..60fdd4b 100644
--- a/R/meta_run.R
+++ b/R/meta_run.R
@@ -27,15 +27,17 @@
 #' @export
 #'
 #' @examples
-#' meta <- meta_example()
-#' ae_summary <- function(...) {
-#'   paste("results of", deparse(match.call(), nlines = 1))
+#' if (interactive()) {
+#'   meta <- meta_example()
+#'   ae_summary <- function(...) {
+#'     "results of ae_summary"
+#'   }
+#'   ae_specific <- function(...) {
+#'     "results of ae_specific"
+#'   }
+#'   meta_run(meta)
+#'   meta_run(meta, i = 2)
 #' }
-#' ae_specific <- function(...) {
-#'   paste("results of", deparse(match.call(), nlines = 1))
-#' }
-#' meta_run(meta)
-#' meta_run(meta, i = 2)
 meta_run <- function(meta, i = NULL, ...) {
   if (is.null(i)) i <- 1:nrow(meta$plan)
   call <- spec_call_program(meta, ...)
diff --git a/R/meta_validate.R b/R/meta_validate.R
index d6dc24e..6b137f7 100644
--- a/R/meta_validate.R
+++ b/R/meta_validate.R
@@ -40,6 +40,8 @@ meta_validate <- function(meta) {
     stop(".$plan must contain all required variable names: 'mock', 'analysis', 'population', 'observation', 'parameter'")
   }
 
+  meta$data_population
+  meta$population
   # Check id variable
   lapply(c(meta$population, meta$observation), function(x) {
     if (is.null(x$id)) {
@@ -86,5 +88,17 @@ meta_validate <- function(meta) {
     }
   })
 
+  # check group factor level are the same
+  u_plan <- unique(meta$plan[, c("population", "observation")])
+  for (i in 1:nrow(u_plan)) {
+    key_pop <- u_plan[i, "population"]
+    key_obs <- u_plan[i, "observation"]
+    level_pop <- levels(meta$data_population[[metalite::collect_adam_mapping(meta, key_pop)$group]])
+    level_obs <- levels(meta$data_observation[[metalite::collect_adam_mapping(meta, key_obs)$group]])
+    if (!all(level_pop == level_obs)) {
+      stop("Inconsistent group level: the levels of group variable from population and observation datasets are not the same")
+    }
+  }
+
   meta
 }
diff --git a/man/meta_run.Rd b/man/meta_run.Rd
index 2152a63..d82f35f 100644
--- a/man/meta_run.Rd
+++ b/man/meta_run.Rd
@@ -20,13 +20,15 @@ Executed analysis based on the analysis plan.
 Execute analysis based on the analysis plan
 }
 \examples{
-meta <- meta_example()
-ae_summary <- function(...) {
-  paste("results of", deparse(match.call(), nlines = 1))
+if(interactive()){
+  meta <- meta_example()
+  ae_summary <- function(...) {
+    "results of ae_summary"
+  }
+  ae_specific <- function(...) {
+    "results of ae_specific"
+  }
+  meta_run(meta)
+  meta_run(meta, i = 2)
 }
-ae_specific <- function(...) {
-  paste("results of", deparse(match.call(), nlines = 1))
-}
-meta_run(meta)
-meta_run(meta, i = 2)
 }
diff --git a/tests/testthat/_snaps/independent-testing-meta_run.md b/tests/testthat/_snaps/independent-testing-meta_run.md
deleted file mode 100644
index e6fea2f..0000000
--- a/tests/testthat/_snaps/independent-testing-meta_run.md
+++ /dev/null
@@ -1,60 +0,0 @@
-# all analysis based on the analysis plan would be executed
-
-    Code
-      meta_run(meta)
-    Output
-      $`ae_summary(meta = meta, population = 'apat', observation = 'wk12', parameter = 'any;rel;ser')`
-      [1] "results of ae_summary(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_summary(meta = meta, population = 'apat', observation = 'wk24', parameter = 'any;rel;ser')`
-      [1] "results of ae_summary(meta = meta, population = \"apat\", observation = \"wk24\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk12', parameter = 'any')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk24', parameter = 'any')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk24\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk12', parameter = 'aeosi')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk24', parameter = 'aeosi')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk24\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk12', parameter = 'rel')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk24', parameter = 'rel')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk24\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk12', parameter = 'ser')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk24', parameter = 'ser')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk24\", "
-      
-
-# only the first analysis based on the analysis plan would be executed
-
-    Code
-      meta_run(meta, i = 1)
-    Output
-      $`ae_summary(meta = meta, population = 'apat', observation = 'wk12', parameter = 'any;rel;ser')`
-      [1] "results of ae_summary(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-
-# selected analysis based on the analysis plan would be executed
-
-    Code
-      meta_run(meta, i = c(1, 3, 5))
-    Output
-      $`ae_summary(meta = meta, population = 'apat', observation = 'wk12', parameter = 'any;rel;ser')`
-      [1] "results of ae_summary(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk12', parameter = 'any')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-      $`ae_specific(meta = meta, population = 'apat', observation = 'wk12', parameter = 'aeosi')`
-      [1] "results of ae_specific(meta = meta, population = \"apat\", observation = \"wk12\", "
-      
-
diff --git a/tests/testthat/test-independent-testing-meta_run.R b/tests/testthat/test-independent-testing-meta_run.R
index 25b9ce8..d09a43f 100644
--- a/tests/testthat/test-independent-testing-meta_run.R
+++ b/tests/testthat/test-independent-testing-meta_run.R
@@ -1,15 +1,24 @@
 # Create example `meta_adam` object
 meta <- meta_example()
 
-# Snapshot testing
+ae_summary <- function(meta, population, observation, parameter) {
+  message("run ae_summary")
+  return(NULL)
+}
+
+ae_specific <- function(meta, population, observation, parameter) {
+  message("run ae_specific")
+  return(NULL)
+}
+
 test_that("all analysis based on the analysis plan would be executed", {
-  expect_snapshot(meta_run(meta))
+  expect_null(meta_run(meta)[[1]])
 })
 
 test_that("only the first analysis based on the analysis plan would be executed", {
-  expect_snapshot(meta_run(meta, i = 1))
+  expect_null(meta_run(meta, i = 1)[[1]])
 })
 
 test_that("selected analysis based on the analysis plan would be executed", {
-  expect_snapshot(meta_run(meta, i = c(1, 3, 5)))
+  expect_null(meta_run(meta, i = c(1, 3, 5))[[1]])
 })
diff --git a/tests/testthat/test-meta_validate.R b/tests/testthat/test-meta_validate.R
index 96393c7..a4b351a 100644
--- a/tests/testthat/test-meta_validate.R
+++ b/tests/testthat/test-meta_validate.R
@@ -1,6 +1,5 @@
-meta <- meta_example()
-
 test_that("Check data_type", {
+  meta <- meta_example()
   meta$data_population <- NULL
   expect_error(meta_validate(meta))
 
@@ -13,25 +12,32 @@ test_that("Check data_type", {
   expect_error(meta_validate(meta))
 })
 
+test_that("Check group factor level", {
+  meta <- meta_example()
+  meta$data_population$TRTA <- factor(meta$data_population$TRTA, c("Placebo", "Xanomeline High Dose", "Xanomeline Low Dose"))
+  expect_error(meta_validate(meta))
+})
 
 test_that("Check plan variable name", {
+  meta <- meta_example()
   names(meta$plan)[5] <- "param"
   expect_error(meta_validate(meta))
 })
 
-
-
 test_that("Check id variable", {
+  meta <- meta_example()
   meta$population$apat$id <- "id"
   expect_error(meta_validate(meta))
 })
 
 test_that("Check label variable", {
+  meta <- meta_example()
   meta$population$apat$label <- NULL
   expect_warning(meta_validate(meta))
 })
 
 test_that("Check observation variables in the datasets", {
+  meta <- meta_example()
   meta$observation$wk12$id <- "ID"
   expect_error(meta_validate(meta))