diff --git a/pkg/experiment/local/assignment_filter.go b/pkg/experiment/local/assignment_filter.go
index 9fd07a1..ed223e6 100644
--- a/pkg/experiment/local/assignment_filter.go
+++ b/pkg/experiment/local/assignment_filter.go
@@ -19,6 +19,9 @@ func newAssignmentFilter(size int) *assignmentFilter {
 }
 
 func (f *assignmentFilter) shouldTrack(assignment *assignment) bool {
+	if len(*assignment.results) == 0 {
+		return false
+	}
 	canonicalAssignment := assignment.Canonicalize()
 	f.mu.Lock()
 	track, found := f.cache.Get(canonicalAssignment)
diff --git a/pkg/experiment/local/assignment_filter_test.go b/pkg/experiment/local/assignment_filter_test.go
index d7639d6..ac9b75a 100644
--- a/pkg/experiment/local/assignment_filter_test.go
+++ b/pkg/experiment/local/assignment_filter_test.go
@@ -167,14 +167,14 @@ func TestEmptyResult(t *testing.T) {
 	assignment2 := newAssignment(user1, results)
 	assignment3 := newAssignment(user2, results)
 	filter := newAssignmentFilter(100)
-	if !filter.shouldTrack(assignment1) {
-		t.Errorf("Assignment1 should be tracked")
+	if filter.shouldTrack(assignment1) {
+		t.Errorf("Assignment1 should not be tracked")
 	}
 	if filter.shouldTrack(assignment2) {
 		t.Errorf("Assignment2 should not be tracked")
 	}
-	if !filter.shouldTrack(assignment3) {
-		t.Errorf("Assignment3 should be tracked")
+	if filter.shouldTrack(assignment3) {
+		t.Errorf("Assignment3 should not be tracked")
 	}
 }