diff --git a/NAMESPACE b/NAMESPACE
index 4e2f402..38efd0e 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -27,3 +27,4 @@ export(checkData)
 export(checkParameter)
 export(createData)
 export(testListParameter)
+export(testpredParameter)
diff --git a/R/rmaMVModel.R b/R/rmaMVModel.R
index e353e22..adc1cec 100644
--- a/R/rmaMVModel.R
+++ b/R/rmaMVModel.R
@@ -36,6 +36,20 @@ rmaMVModel <- function(yi,vi,measure,d,pred1=NULL,pred2=NULL,nesting=NULL) {
   if(!is.null(nesting)){
     nesting <- jsonlite::fromJSON(nesting)
   }
+  if(!is.null(pred1)){
+    # Parse the JSON string into a list
+    pred1<-jsonlite::fromJSON(pred1)
+
+    # Convert the list to a vector
+    pred1 <- unlist(pred1)
+  }
+  if(!is.null(pred2)){
+    # Parse the JSON string into a list
+    pred2<-jsonlite::fromJSON(pred2)
+
+    # Convert the list to a vector
+    pred2 <- unlist(pred2)
+  }
 
   checkParameter(dat,c(yi,vi))
 
diff --git a/R/testFunctions.R b/R/testFunctions.R
index 1549e80..144a46c 100644
--- a/R/testFunctions.R
+++ b/R/testFunctions.R
@@ -20,3 +20,17 @@ testListParameter <- function(nesting = NULL) {
   nest2 <- list(~1 | outcome_ID, ~1 | sample_ID, ~1 | report_ID)
   print(nest2)
 }
+
+
+testpredParameter<-function(pred1){
+
+
+  # Parse the JSON string into a list
+  pred1<-jsonlite::fromJSON(pred1)
+
+  # Convert the list to a vector
+  pred1 <- unlist(pred1)
+
+    print(pred1)
+  pred1["value"]
+}