diff --git a/read_data.R b/read_data.R
index de96a05..803d051 100755
--- a/read_data.R
+++ b/read_data.R
@@ -61,6 +61,12 @@ if (table(adult_df$adult == 1)[[1]] == nrow(adult_df) ){
 # extract the flu positive population
 fp_adults = adult_df[adult_df$flustat == 1,]
 
+if (table(fp_adults$flustat == 1)[[1]] == nrow(fp_adults) ){
+  cat ("PASS: adult df extracted successfully")
+} else{
+  cat ("FAIL: adult df number mismatch!")
+}
+
 #============
 # hc
 #============