diff --git a/src/lp/nack-header.cpp b/src/lp/nack-header.cpp
index 3bbc985..f289c86 100644
--- a/src/lp/nack-header.cpp
+++ b/src/lp/nack-header.cpp
@@ -46,6 +46,19 @@
   return os;
 }
 
+bool
+isLessSevere(lp::NackReason x, lp::NackReason y)
+{
+  if (x == lp::NackReason::NONE) {
+    return false;
+  }
+  if (y == lp::NackReason::NONE) {
+    return true;
+  }
+
+  return static_cast<int>(x) < static_cast<int>(y);
+}
+
 NackHeader::NackHeader()
   : m_reason(NackReason::NONE)
 {
diff --git a/src/lp/nack-header.hpp b/src/lp/nack-header.hpp
index 0c034f4..e4b8c14 100644
--- a/src/lp/nack-header.hpp
+++ b/src/lp/nack-header.hpp
@@ -46,6 +46,13 @@
 std::ostream&
 operator<<(std::ostream& os, NackReason reason);
 
+/** \brief compare NackReason for severity
+ *
+ *  lp::NackReason::NONE is treated as most severe
+ */
+bool
+isLessSevere(lp::NackReason x, lp::NackReason y);
+
 /**
  * \brief represents a Network NACK header
  */