diff --git a/R/helper_funs.R b/R/helper_funs.R
index 718c3fa..c7d908c 100644
--- a/R/helper_funs.R
+++ b/R/helper_funs.R
@@ -74,7 +74,7 @@ gam_to_df <- function(model = NULL, pred = NULL) {
   plot_df <- no_plot(model) # nolint
 
   # get list index of spec. predictor
-  set_pred <- which(grepl(pred, plot_df))
+  set_pred <- grep(paste0("\\b", pred, "\\b"), plot_df)
 
   df <- data.frame(
     x = plot_df[[set_pred]]$x,