diff --git a/sparta/sparta/report/Report.hpp b/sparta/sparta/report/Report.hpp
index 3149a0b106..7e79336738 100644
--- a/sparta/sparta/report/Report.hpp
+++ b/sparta/sparta/report/Report.hpp
@@ -379,7 +379,7 @@ namespace sparta
                 r_.add(ctr, name);
                 return *this;
             }
-            StatAdder& operator()(TreeNode* n,
+            StatAdder& operator()(const TreeNode* n,
                                   const std::string& name="") {
                 r_.add(n, name);
                 return *this;
@@ -435,7 +435,7 @@ namespace sparta
          * \param n The TreeNode to add
          * \param name The name of the item in the report
          */
-        StatAdder add(TreeNode* n, const std::string& name="");
+        StatAdder add(const TreeNode* n, const std::string& name="");
 
         /*!
          * \brief Add a single Expression parsed at the current context for this
diff --git a/sparta/sparta/statistics/StatisticInstance.hpp b/sparta/sparta/statistics/StatisticInstance.hpp
index 8c189c8e27..aa2bd72ac5 100644
--- a/sparta/sparta/statistics/StatisticInstance.hpp
+++ b/sparta/sparta/statistics/StatisticInstance.hpp
@@ -44,7 +44,7 @@ namespace sparta
          * \note Stream insertion operator can be used to add more text to the
          * reason.
          */
-        ReversedStatisticRange(const std::string & reason) :
+        explicit ReversedStatisticRange(const std::string & reason) :
             SpartaException(reason)
         { }
 
@@ -67,7 +67,7 @@ namespace sparta
          * \note Stream insertion operator can be used to add more text to the
          * reason.
          */
-        FutureStatisticRange(const std::string & reason) :
+        explicit FutureStatisticRange(const std::string & reason) :
             SpartaException(reason)
         { }
 
@@ -128,7 +128,7 @@ namespace sparta
          * \note You *must* set the context (setContext) after this
          *       call.  The Expression might or might not know the context for the Scheduler
          */
-        StatisticInstance(statistics::expression::Expression&& expr) :
+        explicit StatisticInstance(statistics::expression::Expression&& expr) :
             stat_expr_(expr)
         { }
 
@@ -136,7 +136,7 @@ namespace sparta
          * \brief Construct with a StatisticDef or Counter as a TreeNode*
          * \param node Must be an interface to a StatisticDef or a Counter
          */
-        StatisticInstance(const TreeNode* node) :
+        explicit StatisticInstance(const TreeNode* node) :
             StatisticInstance(nullptr, nullptr, nullptr, node, nullptr)
         { }
 
diff --git a/sparta/src/Report.cpp b/sparta/src/Report.cpp
index fd7571e758..be2e7eebeb 100644
--- a/sparta/src/Report.cpp
+++ b/sparta/src/Report.cpp
@@ -1225,7 +1225,7 @@ Report::StatAdder Report::add(CounterBase* ctr, const std::string& name) {
     return Report::StatAdder(*this);
 }
 
-Report::StatAdder Report::add(TreeNode* n, const std::string& name) {
+Report::StatAdder Report::add(const TreeNode* n, const std::string& name) {
     sparta_assert(n);
     if(name != "" && stat_names_.find(name) != stat_names_.end()){
         throw SpartaException("There is already a statistic instance in this Report (")