diff --git a/interface/Analyzer.h b/interface/Analyzer.h
index 3b7fcfd..d3590de 100644
--- a/interface/Analyzer.h
+++ b/interface/Analyzer.h
@@ -20,17 +20,22 @@
 #include <map>
 
 class CategoryManager;
+class AnalyzersManager;
+class ExTreeMaker;
 
 namespace Framework {
 
     class Analyzer {
+        friend class ::ExTreeMaker;
+
         public:
+
             Analyzer(const std::string& name, const ROOT::TreeGroup& tree_, const edm::ParameterSet& config):
                 m_name(name),
                 tree(tree_) {
                 }
 
-            virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const CategoryManager&) = 0;
+            virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const AnalyzersManager&, const CategoryManager&) = 0;
             virtual void doConsumes(const edm::ParameterSet&, edm::ConsumesCollector&& collector) {}
 
             virtual void registerCategories(CategoryManager& manager, const edm::ParameterSet& config) {}
@@ -47,6 +52,17 @@ namespace Framework {
         protected:
             std::string m_name;
             ROOT::TreeGroup tree;
+
+        private:
+            bool hasRun() const {
+                return m_run;
+            }
+
+            void setRun(bool run) {
+                m_run = run;
+            }
+
+            bool m_run; //< A flag indicating if the analyzer has already been run for this event
     };
 
 }
diff --git a/interface/BTagsAnalyzer.h b/interface/BTagsAnalyzer.h
index 07b7d4e..865fec5 100644
--- a/interface/BTagsAnalyzer.h
+++ b/interface/BTagsAnalyzer.h
@@ -14,7 +14,7 @@ class BTagsAnalyzer: public Framework::Analyzer {
             m_discr_name(config.getUntrackedParameter<std::string>("discr_name")) 
             { }
 
-        virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const CategoryManager&) override;
+        virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const AnalyzersManager&, const CategoryManager&) override;
 
         BRANCH(indices, std::vector<uint8_t>);
 
diff --git a/interface/DileptonAnalyzer.h b/interface/DileptonAnalyzer.h
index 1c2cde4..d7d34c4 100644
--- a/interface/DileptonAnalyzer.h
+++ b/interface/DileptonAnalyzer.h
@@ -22,7 +22,7 @@ class DileptonAnalyzer: public Framework::Analyzer {
                 m_electron_tight_wp_name = config.getUntrackedParameter<std::string>("electrons_tight_wp_name", "cutBasedElectronID-Spring15-50ns-V1-standalone-tight");
         }
 
-        virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const CategoryManager&) override;
+        virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const AnalyzersManager&, const CategoryManager&) override;
 
         virtual void registerCategories(CategoryManager& manager, const edm::ParameterSet&) override;
 
diff --git a/interface/Producer.h b/interface/Producer.h
index ff0af61..a6a4893 100644
--- a/interface/Producer.h
+++ b/interface/Producer.h
@@ -17,9 +17,13 @@
 #include <vector>
 #include <map>
 
+class ExTreeMaker;
+
 namespace Framework {
 
     class Producer {
+        friend class ::ExTreeMaker;
+
         public:
             Producer(const std::string& name, const ROOT::TreeGroup& tree_, const edm::ParameterSet& config):
                 m_name(name),
@@ -41,6 +45,17 @@ namespace Framework {
         protected:
             std::string m_name;
             ROOT::TreeGroup tree;
+
+        private:
+            bool hasRun() const {
+                return m_run;
+            }
+
+            void setRun(bool run) {
+                m_run = run;
+            }
+
+            bool m_run; //< A flag indicating if the analyzer has already been run for this event
     };
 
 }
diff --git a/interface/TestAnalyzer.h b/interface/TestAnalyzer.h
index e7b2794..c84e902 100644
--- a/interface/TestAnalyzer.h
+++ b/interface/TestAnalyzer.h
@@ -38,7 +38,7 @@ class TestAnalyzer: public Framework::Analyzer {
 
         }
 
-        virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const CategoryManager&) override;
+        virtual void analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager&, const AnalyzersManager&, const CategoryManager&) override;
 
         virtual void registerCategories(CategoryManager& manager, const edm::ParameterSet& config) {
             manager.new_category<TwoMuonsCategory>("two_muons", "At least two muons category", config);
diff --git a/plugins/TestAnalyzer.cc b/plugins/TestAnalyzer.cc
index e6681a4..fa63084 100644
--- a/plugins/TestAnalyzer.cc
+++ b/plugins/TestAnalyzer.cc
@@ -3,11 +3,15 @@
 #include <cp3_llbb/Framework/interface/GenParticlesProducer.h>
 #include <cp3_llbb/Framework/interface/JetsProducer.h>
 
+#include <cp3_llbb/Framework/interface/DileptonAnalyzer.h>
 
-void TestAnalyzer::analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager& producers, const CategoryManager& categories) {
+
+void TestAnalyzer::analyze(const edm::Event&, const edm::EventSetup&, const ProducersManager& producers, const AnalyzersManager& analyzers, const CategoryManager& categories) {
 
     const JetsProducer& jets = producers.get<JetsProducer>("jets");
 
+    const DileptonAnalyzer& di = analyzers.get<DileptonAnalyzer>("dilepton");
+
 /*
     if (producers.exists("gen_particles")) {
         const GenParticlesProducer& gp = dynamic_cast<const GenParticlesProducer&>(producers.get("gen_particles"));
diff --git a/src/BTagsAnalyzer.cc b/src/BTagsAnalyzer.cc
index 624b610..1b7a55a 100644
--- a/src/BTagsAnalyzer.cc
+++ b/src/BTagsAnalyzer.cc
@@ -2,7 +2,7 @@
 
 #include <cp3_llbb/Framework/interface/JetsProducer.h>
 
-void BTagsAnalyzer::analyze(const edm::Event& event, const edm::EventSetup&, const ProducersManager& producers, const CategoryManager& categories) {
+void BTagsAnalyzer::analyze(const edm::Event& event, const edm::EventSetup&, const ProducersManager& producers, const AnalyzersManager& analyzers, const CategoryManager& categories) {
     
     const JetsProducer& jets = producers.get<JetsProducer>("jets");
 
diff --git a/src/DileptonAnalyzer.cc b/src/DileptonAnalyzer.cc
index 197b85d..c8b1192 100644
--- a/src/DileptonAnalyzer.cc
+++ b/src/DileptonAnalyzer.cc
@@ -41,7 +41,7 @@ void DileptonAnalyzer::registerCategories(CategoryManager& manager, const edm::P
     }
 }
 
-void DileptonAnalyzer::analyze(const edm::Event& event, const edm::EventSetup&, const ProducersManager& producers, const CategoryManager& categories) {
+void DileptonAnalyzer::analyze(const edm::Event& event, const edm::EventSetup&, const ProducersManager& producers, const AnalyzersManager& analyzers, const CategoryManager& categories) {
 
 // ***** ***** *****
 // Get all dilepton objects out of the event
diff --git a/src/Framework.cc b/src/Framework.cc
index 43f5fb1..1e7329c 100644
--- a/src/Framework.cc
+++ b/src/Framework.cc
@@ -179,8 +179,10 @@ void ExTreeMaker::produce(edm::Event& iEvent, const edm::EventSetup& iSetup) {
     if (! should_continue)
         return;
 
-    for (auto& producer: m_producers)
+    for (auto& producer: m_producers) {
         producer.second->produce(iEvent, iSetup);
+        producer.second->setRun(true);
+    }
 
     should_continue = m_categories->evaluate_pre_analyzers(*m_producers_manager);
     if (! should_continue) {
@@ -189,8 +191,10 @@ void ExTreeMaker::produce(edm::Event& iEvent, const edm::EventSetup& iSetup) {
         return;
     }
 
-    for (auto& analyzer: m_analyzers)
-        analyzer->analyze(iEvent, iSetup, *m_producers_manager, *m_categories);
+    for (auto& analyzer: m_analyzers) {
+        analyzer->analyze(iEvent, iSetup, *m_producers_manager, *m_analyzers_manager, *m_categories);
+        analyzer->setRun(true);
+    }
 
     if (m_categories->evaluate_post_analyzers(*m_producers_manager, *m_analyzers_manager))
         m_wrapper->fill();
@@ -198,6 +202,12 @@ void ExTreeMaker::produce(edm::Event& iEvent, const edm::EventSetup& iSetup) {
         m_wrapper->reset();
 
     m_categories->reset();
+
+    for (auto& analyzer: m_analyzers)
+        analyzer->setRun(false);
+
+    for (auto& producer: m_producers)
+        producer.second->setRun(false);
 }
 
 
@@ -289,7 +299,14 @@ const Framework::Producer& ExTreeMaker::getProducer(const std::string& name) con
         throw edm::Exception(edm::errors::NotFound, details.str());
     }
 
-    return *producer->second;
+    Framework::Producer& p = *producer->second;
+    if (! p.hasRun()) {
+        std::stringstream details;
+        details << "Producer '" << name << "' has not been run yet for this event. Please check the scheduling of your producers";
+        throw edm::Exception(edm::errors::NotFound, details.str());
+    }
+
+    return p;
 }
 
 bool ExTreeMaker::producerExists(const std::string& name) const {
@@ -305,7 +322,14 @@ const Framework::Analyzer& ExTreeMaker::getAnalyzer(const std::string& name) con
         throw edm::Exception(edm::errors::NotFound, details.str());
     }
 
-    return *m_analyzers[std::distance(m_analyzers_name.begin(), it)];
+    Framework::Analyzer& analyzer = *m_analyzers[std::distance(m_analyzers_name.begin(), it)];
+    if (! analyzer.hasRun()) {
+        std::stringstream details;
+        details << "Analyzer '" << name << "' has not been run yet for this event. Please check the scheduling of your analyzers";
+        throw edm::Exception(edm::errors::NotFound, details.str());
+    }
+
+    return analyzer;
 }
 
 bool ExTreeMaker::analyzerExists(const std::string& name) const {