diff --git a/moses/LatticeMBR.cpp b/moses/LatticeMBR.cpp
index 9ea21d5db..b6fa14757 100644
--- a/moses/LatticeMBR.cpp
+++ b/moses/LatticeMBR.cpp
@@ -499,7 +499,7 @@ bool ascendingCoverageCmp(const Hypothesis* a, const Hypothesis* b)
   return a->GetWordsBitmap().GetNumWordsCovered() <  b->GetWordsBitmap().GetNumWordsCovered();
 }
 
-void getLatticeMBRNBest(Manager& manager, TrellisPathList& nBestList,
+void getLatticeMBRNBest(const Manager& manager, const TrellisPathList& nBestList,
                         vector<LatticeMBRSolution>& solutions, size_t n)
 {
   const StaticData& staticData = StaticData::Instance();
@@ -546,7 +546,7 @@ void getLatticeMBRNBest(Manager& manager, TrellisPathList& nBestList,
   VERBOSE(2,"LMBR Score: " << solutions[0].GetScore() << endl);
 }
 
-vector<Word> doLatticeMBR(Manager& manager, TrellisPathList& nBestList)
+vector<Word> doLatticeMBR(const Manager& manager, const TrellisPathList& nBestList)
 {
 
   vector<LatticeMBRSolution> solutions;
@@ -554,7 +554,7 @@ vector<Word> doLatticeMBR(Manager& manager, TrellisPathList& nBestList)
   return solutions.at(0).GetWords();
 }
 
-const TrellisPath doConsensusDecoding(Manager& manager, TrellisPathList& nBestList)
+const TrellisPath doConsensusDecoding(const Manager& manager, const TrellisPathList& nBestList)
 {
   static const int BLEU_ORDER = 4;
   static const float SMOOTH = 1;
diff --git a/moses/LatticeMBR.h b/moses/LatticeMBR.h
index 47d6da3c4..5fa47949d 100644
--- a/moses/LatticeMBR.h
+++ b/moses/LatticeMBR.h
@@ -137,15 +137,15 @@ void pruneLatticeFB(Lattice & connectedHyp, std::map < const Moses::Hypothesis*,
                     const std::vector< float> & estimatedScores, const Moses::Hypothesis*, size_t edgeDensity,float scale);
 
 //Use the ngram scores to rerank the nbest list, return at most n solutions
-void getLatticeMBRNBest(Moses::Manager& manager, Moses::TrellisPathList& nBestList, std::vector<LatticeMBRSolution>& solutions, size_t n);
+void getLatticeMBRNBest(const Moses::Manager& manager, const Moses::TrellisPathList& nBestList, std::vector<LatticeMBRSolution>& solutions, size_t n);
 //calculate expectated ngram counts, clipping at 1 (ie calculating posteriors) if posteriors==true.
 void calcNgramExpectations(Lattice & connectedHyp, std::map<const Moses::Hypothesis*, std::vector<Edge> >& incomingEdges, std::map<Moses::Phrase,
                            float>& finalNgramScores, bool posteriors);
 void GetOutputFactors(const Moses::TrellisPath &path, std::vector <Moses::Word> &translation);
 void extract_ngrams(const std::vector<Moses::Word >& sentence, std::map < Moses::Phrase, int >  & allngrams);
 bool ascendingCoverageCmp(const Moses::Hypothesis* a, const Moses::Hypothesis* b);
-std::vector<Moses::Word> doLatticeMBR(Moses::Manager& manager, Moses::TrellisPathList& nBestList);
-const Moses::TrellisPath doConsensusDecoding(Moses::Manager& manager, Moses::TrellisPathList& nBestList);
+std::vector<Moses::Word> doLatticeMBR(const Moses::Manager& manager, const Moses::TrellisPathList& nBestList);
+const Moses::TrellisPath doConsensusDecoding(const Moses::Manager& manager, const Moses::TrellisPathList& nBestList);
 //std::vector<Moses::Word> doConsensusDecoding(Moses::Manager& manager, Moses::TrellisPathList& nBestList);
 
 }