diff --git a/doc/robust.pdf b/doc/robust.pdf
index 3404719b4..ef8dc6fe6 100644
Binary files a/doc/robust.pdf and b/doc/robust.pdf differ
diff --git a/gtsam/linear/NoiseModel.cpp b/gtsam/linear/NoiseModel.cpp
index 206cab3b1..a7b48b034 100644
--- a/gtsam/linear/NoiseModel.cpp
+++ b/gtsam/linear/NoiseModel.cpp
@@ -661,11 +661,6 @@ Robust::shared_ptr Robust::Create(const RobustModel::shared_ptr& robust,
   return shared_ptr(new Robust(robust, gaussian));
 }
 
-// Robust::shared_ptr Robust::Create(
-//   const RobustModel::shared_ptr &robust, const NoiseModel::shared_ptr noise){
-//   return shared_ptr(new Robust(robust,noise));
-// }
-
 /* ************************************************************************* */
 
 }
diff --git a/gtsam/linear/NoiseModel.h b/gtsam/linear/NoiseModel.h
index c8e0e78a5..73484799f 100644
--- a/gtsam/linear/NoiseModel.h
+++ b/gtsam/linear/NoiseModel.h
@@ -94,7 +94,9 @@ namespace gtsam {
       virtual double error(const Vector& v) const = 0;
 
 #ifdef GTSAM_ALLOW_DEPRECATED_SINCE_V4
-      virtual double distance(const Vector& v) const = 0;
+      virtual double distance(const Vector& v) {
+        return error(v) * 2;
+      }
 #endif
 
       virtual void WhitenSystem(std::vector<Matrix>& A, Vector& b) const = 0;
@@ -713,6 +715,11 @@ namespace gtsam {
       { Vector b; Matrix B=A; this->WhitenSystem(B,b); return B; }
       inline virtual Vector unwhiten(const Vector& /*v*/) const
       { throw std::invalid_argument("unwhiten is not currently supported for robust noise models."); }
+#ifdef GTSAM_ALLOW_DEPRECATED_SINCE_V4
+      inline virtual double distance(const Vector& v) {
+        return robust_->loss(this->unweightedWhiten(v).norm());
+      }
+#endif
       // Fold the use of the m-estimator loss(...) function into error(...)
       inline virtual double error(const Vector& v) const
       { return robust_->loss(noise_->mahalanobisDistance(v)); }
@@ -734,9 +741,6 @@ namespace gtsam {
       static shared_ptr Create(
         const RobustModel::shared_ptr &robust, const noiseModel::Base::shared_ptr noise);
 
-      // static shared_ptr Create(
-      //   const RobustModel::shared_ptr &robust, const NoiseModel::shared_ptr noise);
-
     private:
       /** Serialization function */
       friend class boost::serialization::access;