diff --git a/Reconstruction/MET/METReconstruction/METReconstruction/METCaloRegionsTool.h b/Reconstruction/MET/METReconstruction/METReconstruction/METCaloRegionsTool.h
index 9185f40be22c4fda77a44a22e87d0f31f11994c2..6b898d45ba6efc2809020f9633ed4964a7ee77c9 100644
--- a/Reconstruction/MET/METReconstruction/METReconstruction/METCaloRegionsTool.h
+++ b/Reconstruction/MET/METReconstruction/METReconstruction/METCaloRegionsTool.h
@@ -113,7 +113,7 @@ namespace met{
       REGIONS_TOTAL
     };
     // CaloRegions human-readable names for enums
-    const static std::string CaloRegionNames[];
+    const static std::string s_CaloRegionNames[];
     
   private:
     // Default constructor: 
diff --git a/Reconstruction/MET/METReconstruction/METReconstruction/METTruthAssociator.h b/Reconstruction/MET/METReconstruction/METReconstruction/METTruthAssociator.h
index fc5e952721ced230bd16af2dff923bead652ea07..8a748a654220b03c9efebc676f595b52f806d0c3 100644
--- a/Reconstruction/MET/METReconstruction/METReconstruction/METTruthAssociator.h
+++ b/Reconstruction/MET/METReconstruction/METReconstruction/METTruthAssociator.h
@@ -91,7 +91,7 @@ namespace met{
     std::string m_recoMuKey;
     std::string m_recoGamKey;
     std::string m_recoTauKey;
-    std::string m_truthPartKey;
+    std::string m_truthEventKey;
  
     /// Default constructor: 
     METTruthAssociator();
diff --git a/Reconstruction/MET/METReconstruction/Root/METCaloRegionsTool.cxx b/Reconstruction/MET/METReconstruction/Root/METCaloRegionsTool.cxx
index afc8070a30bce86fcffde915d2b40eeaeed9d162..09ba9ad41448e3b704d65730a0e55326b4e7e323 100644
--- a/Reconstruction/MET/METReconstruction/Root/METCaloRegionsTool.cxx
+++ b/Reconstruction/MET/METReconstruction/Root/METCaloRegionsTool.cxx
@@ -33,8 +33,8 @@ namespace met {
   using xAOD::MissingET;
   using xAOD::MissingETContainer;
 
-  // Initialize CaloRegionNames
-  const std::string METCaloRegionsTool::CaloRegionNames[METCaloRegionsTool::REGIONS_TOTAL] = 
+  // Initialize s_CaloRegionNames
+  const std::string METCaloRegionsTool::s_CaloRegionNames[METCaloRegionsTool::REGIONS_TOTAL] = 
   {
     "EMB",
     "EME",
@@ -127,7 +127,7 @@ namespace met {
         metCont->push_back( new MissingET(0.,0.,0.) ); 
       }
       // Set Name and Source
-      metCont->at(i)->setName( CaloRegionNames[i] );      
+      metCont->at(i)->setName( s_CaloRegionNames[i] );      
       metCont->at(i)->setSource( source );      
     }
     // The last term is Trigger MET if asked for by the user
diff --git a/Reconstruction/MET/METReconstruction/Root/METJetAssocTool.cxx b/Reconstruction/MET/METReconstruction/Root/METJetAssocTool.cxx
index 47ed05704730fcc288340d8c166132ebb7ebaa71..bc64c6b431eb3b7dfe797370766501c00b1ff046 100644
--- a/Reconstruction/MET/METReconstruction/Root/METJetAssocTool.cxx
+++ b/Reconstruction/MET/METReconstruction/Root/METJetAssocTool.cxx
@@ -39,7 +39,6 @@ namespace met {
     AsgTool(name),
     METAssociator(name)
   {
-    declareProperty( "IgnoreJetConst",    m_skipconst = false               );
     declareProperty( "MatchRadius",       m_matchRadius = 0.4               );
   }
 
diff --git a/Reconstruction/MET/METReconstruction/Root/METTruthAssociator.cxx b/Reconstruction/MET/METReconstruction/Root/METTruthAssociator.cxx
index 99d3587634534b5a7390d54f38eaa658db68c10b..f48f1915a9c26950260b05d7f50e9b07ecb3ebdd 100644
--- a/Reconstruction/MET/METReconstruction/Root/METTruthAssociator.cxx
+++ b/Reconstruction/MET/METReconstruction/Root/METTruthAssociator.cxx
@@ -22,7 +22,8 @@
 #include "xAODEgamma/ElectronContainer.h"
 #include "xAODEgamma/PhotonContainer.h"
 #include "xAODTau/TauJetContainer.h"
-#include "xAODTruth/TruthParticleContainer.h"
+#include "xAODTruth/TruthEventContainer.h"
+#include "AthContainers/ConstDataVector.h"
 
 // Helpers
 #include "xAODEgamma/EgammaxAODHelpers.h"
@@ -49,7 +50,7 @@ namespace met {
     declareProperty("RecoGamKey", m_recoGamKey = "Photons"   );
     declareProperty("RecoTauKey", m_recoTauKey = "TauJets"   );
 
-    declareProperty("TruthPartKey", m_truthPartKey = "TruthParticles" );
+    declareProperty("TruthEventKey", m_truthEventKey = "TruthEvents" );
   }
 
   // Destructor
@@ -211,14 +212,22 @@ namespace met {
 
     ATH_MSG_VERBOSE("Added core terms.");
 
-    const TruthParticleContainer* truthParticleCont(0);
-    if( evtStore()->retrieve(truthParticleCont, m_truthPartKey).isFailure() ) {
-      ATH_MSG_WARNING("Unable to retrieve input truthParticle container " << m_truthPartKey);
+    const TruthEventContainer* truthEventCont(0);
+    if( evtStore()->retrieve(truthEventCont, m_truthEventKey).isFailure() ) {
+      ATH_MSG_WARNING("Unable to retrieve input truthEvent container " << m_truthEventKey);
       return StatusCode::FAILURE;
     }
 
-    const IParticleContainer* uniqueTruth = metMap->getUniqueSignals(truthParticleCont,MissingETBase::UsageHandler::TruthParticle);
-    ATH_MSG_VERBOSE("Extracted " << uniqueTruth->size() << "/" << truthParticleCont->size()
+    // First truth event is the hard scatter
+    const TruthEvent* hsevent = truthEventCont->front();
+    ConstDataVector<TruthParticleContainer> truthParticleCont(SG::VIEW_ELEMENTS);
+    for(size_t itp=0; itp<hsevent->nTruthParticles(); ++itp) {
+      truthParticleCont.push_back(hsevent->truthParticle(itp));
+      ATH_MSG_VERBOSE("Extracted truth particle with index " << hsevent->truthParticle(itp)->index() );
+    }
+
+    const IParticleContainer* uniqueTruth = metMap->getUniqueSignals(truthParticleCont.asDataVector(),MissingETBase::UsageHandler::TruthParticle);
+    ATH_MSG_VERBOSE("Extracted " << uniqueTruth->size() << "/" << truthParticleCont.size()
 		    << " unique truth particles.");
     for(const auto& part : *uniqueTruth) {
       const xAOD::TruthParticle* truth = static_cast<const xAOD::TruthParticle*>(part);
@@ -279,13 +288,20 @@ namespace met {
     //   if(truth && truth!=eltruth) truthlist.push_back(truth);
     // }
 
-    const TruthParticleContainer* truthParticleCont(0);
-    if( evtStore()->retrieve(truthParticleCont, m_truthPartKey).isFailure() ) {
-      ATH_MSG_WARNING("Unable to retrieve input truthParticle container " << m_truthPartKey);
+    const TruthEventContainer* truthEventCont(0);
+    if( evtStore()->retrieve(truthEventCont, m_truthEventKey).isFailure() ) {
+      ATH_MSG_WARNING("Unable to retrieve input truthEvent container " << m_truthEventKey);
       return StatusCode::FAILURE;
     }
 
-    for(const auto& truth : *truthParticleCont) {
+    // First truth event is the hard scatter
+    const TruthEvent* hsevent = truthEventCont->front();
+    ConstDataVector<TruthParticleContainer> truthParticleCont(SG::VIEW_ELEMENTS);
+    for(size_t itp=0; itp<hsevent->nTruthParticles(); ++itp) {
+      truthParticleCont.push_back(hsevent->truthParticle(itp));
+    }
+
+    for(const auto& truth : truthParticleCont) {
       if(truth->pt()<1) continue;
       // stable
       if(!MC::isGenStable(truth->status(),truth->barcode())) continue;
@@ -353,13 +369,20 @@ namespace met {
     //   }
     // }
 
-    const TruthParticleContainer* truthParticleCont(0);
-    if( evtStore()->retrieve(truthParticleCont, m_truthPartKey).isFailure() ) {
-      ATH_MSG_WARNING("Unable to retrieve input truthParticle container " << m_truthPartKey);
+    const TruthEventContainer* truthEventCont(0);
+    if( evtStore()->retrieve(truthEventCont, m_truthEventKey).isFailure() ) {
+      ATH_MSG_WARNING("Unable to retrieve input truthEvent container " << m_truthEventKey);
       return StatusCode::FAILURE;
     }
 
-    for(const auto& truth : *truthParticleCont) {
+    // First truth event is the hard scatter
+    const TruthEvent* hsevent = truthEventCont->front();
+    ConstDataVector<TruthParticleContainer> truthParticleCont(SG::VIEW_ELEMENTS);
+    for(size_t itp=0; itp<hsevent->nTruthParticles(); ++itp) {
+      truthParticleCont.push_back(hsevent->truthParticle(itp));
+    }
+
+    for(const auto& truth : truthParticleCont) {
       if(truth->pt()<1) continue;
       // stable
       if(!MC::isGenStable(truth->status(),truth->barcode())) continue;
diff --git a/Reconstruction/MET/METReconstruction/Root/METTruthTool.cxx b/Reconstruction/MET/METReconstruction/Root/METTruthTool.cxx
index 2f5092309d550e09f26a9337d66f9fecf605b3c1..55bec9104f70e3339c7e0bfe7648585b3183f387 100644
--- a/Reconstruction/MET/METReconstruction/Root/METTruthTool.cxx
+++ b/Reconstruction/MET/METReconstruction/Root/METTruthTool.cxx
@@ -21,9 +21,13 @@
 #include "xAODMissingET/MissingETAuxComponentMap.h"
 
 // Truth EDM
+#include "xAODTruth/TruthEventContainer.h"
 #include "xAODTruth/TruthParticleContainer.h"
 #include "xAODTruth/TruthVertex.h"
 
+// Base EDM
+#include "AthContainers/ConstDataVector.h"
+
 // Truth Utilities
 #include "TruthUtils/TruthParticleHelpers.h"
 
@@ -33,6 +37,8 @@ namespace met {
   //
   using xAOD::IParticle;
   //
+  using xAOD::TruthEvent;
+  using xAOD::TruthEventContainer;
   using xAOD::TruthParticle;
   using xAOD::TruthParticleContainer;
   //
@@ -199,26 +205,34 @@ namespace met {
 
     ATH_MSG_DEBUG ("In execute: " << name() << "...");
 
-    const TruthParticleContainer* truthCont = 0;
+    const TruthEventContainer* truthEvents = 0;
 
     metTerm->setSource(m_truth_type);
 
     // Retrieve the truth container
-    if ( evtStore()->retrieve(truthCont, m_input_data_key).isFailure() ) {
-      ATH_MSG_WARNING("Unable to retrieve input truth particle container");
+    if ( evtStore()->retrieve(truthEvents, m_input_data_key).isFailure() ) {
+      ATH_MSG_WARNING("Unable to retrieve input truth event container");
       return StatusCode::SUCCESS;
     }
 
+    // First truth event is the hard scatter
+    const TruthEvent* hsevent = truthEvents->front();
+    ConstDataVector<TruthParticleContainer> truthCont(SG::VIEW_ELEMENTS);
+    for(size_t itp=0; itp<hsevent->nTruthParticles(); ++itp) {
+      truthCont.push_back(hsevent->truthParticle(itp));
+      ATH_MSG_VERBOSE("Extracted truth particle with index " << hsevent->truthParticle(itp)->index());
+    }
+
     vector<const IParticle*> signalList;
-    signalList.reserve(truthCont->size());
+    signalList.reserve(truthCont.size());
     // Loop over all truth particles
-    for( TruthParticleContainer::const_iterator iTruth=truthCont->begin(); iTruth!=truthCont->end(); ++iTruth ) {
+    for( const auto& truthp : truthCont ) {
       // Check if truth particles satisfies the requirements
-      if( this->accept(*iTruth) ) {
+      if( this->accept(truthp) ) {
 	// Add the selected truth particles to the list
-	signalList.push_back(*iTruth);
+	signalList.push_back(truthp);
       }
-    } // end loop over truths
+    } // end loop over truth particles
 
     // Loop over the content and add to MET 
     MissingETBase::Types::weight_t unitWeight(1.,1.,1.);
diff --git a/Reconstruction/MET/METReconstruction/python/METAssocConfig.py b/Reconstruction/MET/METReconstruction/python/METAssocConfig.py
index 9421a9a5082c942801c9643f8456806d05c1efef..ac1ff5794b882cd8a72b38edeebb61e26374e90c 100644
--- a/Reconstruction/MET/METReconstruction/python/METAssocConfig.py
+++ b/Reconstruction/MET/METReconstruction/python/METAssocConfig.py
@@ -25,7 +25,7 @@ defaultInputKey = {
    'ClusColl'  :'CaloCalTopoClusters',
    'TrkColl'   :'InDetTrackParticles',
    'PrimVxColl':'PrimaryVertices',
-   'Truth'     :'TruthParticles',
+   'Truth'     :'TruthEvents',
    'LCOCClusColl':'LCOriginTopoClusters',
    'EMOCClusColl':'EMOriginTopoClusters',
    }
diff --git a/Reconstruction/MET/METReconstruction/python/METRecoConfig.py b/Reconstruction/MET/METReconstruction/python/METRecoConfig.py
index 012734561499553d0368e641d422ba7690eb2f71..ceea93c5fd540b6f78fd3e7fba776ac349055c5d 100644
--- a/Reconstruction/MET/METReconstruction/python/METRecoConfig.py
+++ b/Reconstruction/MET/METReconstruction/python/METRecoConfig.py
@@ -31,7 +31,7 @@ defaultInputKey = {
    'SoftClus' :'CaloCalTopoClusters',
    'SoftPFlow':'JetETMissNeutralParticleFlowObjects',
    'PrimaryVx':'PrimaryVertices',
-   'Truth'    :'TruthParticles',
+   'Truth'    :'TruthEvents',
    'Calo'     :'AllCalo',
    'LCOCSoftClus':'LCOriginTopoClusters',
    'EMOCSoftClus':'EMOriginTopoClusters',