diff --git a/outputs.tf b/outputs.tf
index 3c3e83f..21e4ea5 100644
--- a/outputs.tf
+++ b/outputs.tf
@@ -24,7 +24,7 @@ output "role_arn" {
 }
 
 output "security_group_id" {
-  value       = var.subnet_ids != null && var.security_group_config.ids == [] ? aws_security_group.default[0].id : ""
+  value       = var.subnet_ids != null && length(var.security_group_config.ids) == 0 ? aws_security_group.default[0].id : ""
   description = "If the Lambda is deployed into a VPC this will output the security group id"
 }