diff --git a/umi-tools.wdl b/umi-tools.wdl
index 35d54299ff8425090e5beb408857ea7e994fc1f7..2d244c1d9c4206cc1c40b06e98e1af87f3312ddd 100644
--- a/umi-tools.wdl
+++ b/umi-tools.wdl
@@ -96,9 +96,9 @@ task Dedup {
     output {
         File deduppedBam = outputBamPath
         File deduppedBamIndex = outputBamIndex
-        File? editDistance = statsPrefix + "_edit_distance.tsv"
-        File? umiStats = statsPrefix + "_per_umi.tsv"
-        File? positionStats = statsPrefix + "_per_umi_per_position.tsv"
+        File? editDistance = "~{statsPrefix}_edit_distance.tsv"
+        File? umiStats = "~{statsPrefix}_per_umi.tsv"
+        File? positionStats =  "~{statsPrefix}_per_umi_per_position.tsv"
     }
 
     runtime {