diff --git a/Examples/RegistrationITKv4/ImageRegistrationHistogramPlotter.cxx b/Examples/RegistrationITKv4/ImageRegistrationHistogramPlotter.cxx
index 9126f03f704..053b2618177 100644
--- a/Examples/RegistrationITKv4/ImageRegistrationHistogramPlotter.cxx
+++ b/Examples/RegistrationITKv4/ImageRegistrationHistogramPlotter.cxx
@@ -377,7 +377,6 @@ class HistogramWriter
   HistogramToImageFilterPointer m_Filter;
   HistogramFileWriterPointer    m_HistogramFileWriter;
   // Software Guide : EndCodeSnippet
-  std::string m_OutputFile;
 };
 
 // Command - observer invoked after every iteration of the optimizer
diff --git a/Modules/Core/Common/test/itkFixedArrayTest.cxx b/Modules/Core/Common/test/itkFixedArrayTest.cxx
index 723fd0501df..bd5d33ca247 100644
--- a/Modules/Core/Common/test/itkFixedArrayTest.cxx
+++ b/Modules/Core/Common/test/itkFixedArrayTest.cxx
@@ -31,7 +31,7 @@ Set_c_Array(int x[3])
 }
 
 void
-Print_Array(itk::FixedArray<int, 3> x, std::ostream & os)
+Print_Array(const itk::FixedArray<int, 3> & x, std::ostream & os)
 {
   os << '{' << x[0] << ',' << x[1] << ',' << x[2] << '}' << std::endl;
 }
@@ -43,7 +43,7 @@ Print_c_ArrayConst(const int x[3], std::ostream & os)
 }
 
 void
-Print_Array5(itk::FixedArray<int, 5> x, std::ostream & os)
+Print_Array5(const itk::FixedArray<int, 5> & x, std::ostream & os)
 {
   os << '{' << x[0] << ',' << x[1] << ',' << x[2] << ',' << x[3] << ',' << x[4] << '}' << std::endl;
 }
diff --git a/Modules/Core/Common/test/itkMathRoundTest.cxx b/Modules/Core/Common/test/itkMathRoundTest.cxx
index 8d081f6974e..d7773ab257b 100644
--- a/Modules/Core/Common/test/itkMathRoundTest.cxx
+++ b/Modules/Core/Common/test/itkMathRoundTest.cxx
@@ -17,10 +17,11 @@
  *=========================================================================*/
 
 #include <iostream>
+#include <string_view>
 #include "itkIndex.h"
 
 bool
-math_test_helper(std::string str, bool test)
+math_test_helper(const std::string_view str, bool test)
 {
   if (!test)
   {
diff --git a/Modules/Core/Mesh/test/itkCellInterfaceTest.cxx b/Modules/Core/Mesh/test/itkCellInterfaceTest.cxx
index df097213b01..1dd3b555810 100644
--- a/Modules/Core/Mesh/test/itkCellInterfaceTest.cxx
+++ b/Modules/Core/Mesh/test/itkCellInterfaceTest.cxx
@@ -17,6 +17,7 @@
  *=========================================================================*/
 
 #include <iostream>
+#include <string_view>
 
 #include "itkMesh.h"
 #include "itkPolyLineCell.h"
@@ -44,7 +45,7 @@ using CellAutoPointer = CellType::CellAutoPointer;
 
 template <typename TCell>
 int
-TestCellInterface(std::string name, TCell * aCell)
+TestCellInterface(const std::string_view name, TCell * aCell)
 {
   const CellAutoPointer cell(aCell, true);
 
diff --git a/Modules/Core/QuadEdgeMesh/test/itkQuadEdgeMeshCellInterfaceTest.cxx b/Modules/Core/QuadEdgeMesh/test/itkQuadEdgeMeshCellInterfaceTest.cxx
index c0742e2cd62..143377cbef0 100644
--- a/Modules/Core/QuadEdgeMesh/test/itkQuadEdgeMeshCellInterfaceTest.cxx
+++ b/Modules/Core/QuadEdgeMesh/test/itkQuadEdgeMeshCellInterfaceTest.cxx
@@ -17,6 +17,7 @@
  *=========================================================================*/
 
 #include <iostream>
+#include <string_view>
 
 #include "itkQuadEdgeMesh.h"
 
@@ -66,7 +67,7 @@ class CustomQEPolyVisitor
 // Test the cell interface
 template <typename TCell>
 int
-TestCellInterface(std::string name, TCell * aCell)
+TestCellInterface(const std::string_view name, TCell * aCell)
 {
 
   const CellAutoPointer cell(aCell, true);
@@ -174,7 +175,7 @@ TestCellInterface(std::string name, TCell * aCell)
 
 template <typename TCell>
 int
-TestQECellInterface(std::string name, TCell * aCell)
+TestQECellInterface(const std::string_view name, TCell * aCell)
 {
   std::cout << "-------- " << name << '(' << aCell->GetNameOfClass() << ')' << std::endl;
 
diff --git a/Modules/Core/TestKernel/include/itkTestDriverInclude.h b/Modules/Core/TestKernel/include/itkTestDriverInclude.h
index 89fb5fdb5b2..7ec3254345e 100644
--- a/Modules/Core/TestKernel/include/itkTestDriverInclude.h
+++ b/Modules/Core/TestKernel/include/itkTestDriverInclude.h
@@ -66,7 +66,7 @@ RegressionTestImage(const char *       testImageFilename,
                     double             directionTolerance = 1.0e-6);
 
 extern int
-HashTestImage(const char * testImageFilename, const std::string md5hash);
+HashTestImage(const char * testImageFilename, const std::string & md5hash);
 
 
 extern std::map<std::string, int>
diff --git a/Modules/Core/Transform/test/itkEuler2DTransformTest.cxx b/Modules/Core/Transform/test/itkEuler2DTransformTest.cxx
index 4f6abe5b59a..7f87c14c79a 100644
--- a/Modules/Core/Transform/test/itkEuler2DTransformTest.cxx
+++ b/Modules/Core/Transform/test/itkEuler2DTransformTest.cxx
@@ -26,7 +26,7 @@
 namespace
 {
 bool
-CheckEqual(itk::Point<double, 2> p1, itk::Point<double, 2> p2)
+CheckEqual(const itk::Point<double, 2> & p1, const itk::Point<double, 2> & p2)
 {
   constexpr double epsilon = 1e-5;
 
diff --git a/Modules/Core/Transform/test/itkRigid2DTransformTest.cxx b/Modules/Core/Transform/test/itkRigid2DTransformTest.cxx
index c9e1374e0ca..c57bcdb744a 100644
--- a/Modules/Core/Transform/test/itkRigid2DTransformTest.cxx
+++ b/Modules/Core/Transform/test/itkRigid2DTransformTest.cxx
@@ -23,7 +23,7 @@
 namespace
 {
 bool
-CheckEqual(itk::Point<double, 2> p1, itk::Point<double, 2> p2)
+CheckEqual(const itk::Point<double, 2> & p1, const itk::Point<double, 2> & p2)
 {
   constexpr double epsilon = 1e-10;
   for (unsigned int i = 0; i < 2; ++i)
diff --git a/Modules/Core/Transform/test/itkSimilarity2DTransformTest.cxx b/Modules/Core/Transform/test/itkSimilarity2DTransformTest.cxx
index 7c22b8862d6..07874805deb 100644
--- a/Modules/Core/Transform/test/itkSimilarity2DTransformTest.cxx
+++ b/Modules/Core/Transform/test/itkSimilarity2DTransformTest.cxx
@@ -24,7 +24,7 @@
 namespace
 {
 bool
-CheckEqual(itk::Point<double, 2> p1, itk::Point<double, 2> p2)
+CheckEqual(const itk::Point<double, 2> & p1, const itk::Point<double, 2> & p2)
 {
   constexpr double epsilon = 1e-10;
 
diff --git a/Modules/Filtering/BiasCorrection/test/itkN4BiasFieldCorrectionImageFilterTest.cxx b/Modules/Filtering/BiasCorrection/test/itkN4BiasFieldCorrectionImageFilterTest.cxx
index a73fc5af375..434b73ab127 100644
--- a/Modules/Filtering/BiasCorrection/test/itkN4BiasFieldCorrectionImageFilterTest.cxx
+++ b/Modules/Filtering/BiasCorrection/test/itkN4BiasFieldCorrectionImageFilterTest.cxx
@@ -75,7 +75,7 @@ Convert(std::string optionString)
 
 template <typename TValue>
 std::vector<TValue>
-ConvertVector(std::string optionString)
+ConvertVector(const std::string & optionString)
 {
   std::vector<TValue>    values;
   std::string::size_type crosspos = optionString.find('x', 0);
diff --git a/Modules/Filtering/ImageIntensity/test/itkSymmetricEigenAnalysisImageFilterTest.cxx b/Modules/Filtering/ImageIntensity/test/itkSymmetricEigenAnalysisImageFilterTest.cxx
index f417c9cb4c5..3fc17701a71 100644
--- a/Modules/Filtering/ImageIntensity/test/itkSymmetricEigenAnalysisImageFilterTest.cxx
+++ b/Modules/Filtering/ImageIntensity/test/itkSymmetricEigenAnalysisImageFilterTest.cxx
@@ -96,7 +96,7 @@ class SymmetricEigenAnalysisImageFilterHelper : public SymmetricEigenAnalysisIma
   itkNewMacro(Self);
 
   static int
-  Exercise(itk::EigenValueOrderEnum order, std::string outputFilename)
+  Exercise(itk::EigenValueOrderEnum order, const std::string & outputFilename)
   {
 
     using SymmetricEigenAnalysisImageFilterType = SymmetricEigenAnalysisImageFilter<InputImageType, InternalImageType>;
@@ -202,7 +202,7 @@ class SymmetricEigenAnalysisFixedDimensionImageFilterHelper
   itkNewMacro(Self);
 
   static int
-  Exercise(itk::EigenValueOrderEnum order, std::string outputFilename)
+  Exercise(itk::EigenValueOrderEnum order, const std::string & outputFilename)
   {
 
     using SymmetricEigenAnalysisFixedDimensionImageFilterType =
diff --git a/Modules/Filtering/Path/test/itkContourExtractor2DImageFilterTest.cxx b/Modules/Filtering/Path/test/itkContourExtractor2DImageFilterTest.cxx
index af6a9f2299e..e505145f358 100644
--- a/Modules/Filtering/Path/test/itkContourExtractor2DImageFilterTest.cxx
+++ b/Modules/Filtering/Path/test/itkContourExtractor2DImageFilterTest.cxx
@@ -456,7 +456,7 @@ static itkContourExtractor2DImageFilterTestNamespace::MyVertexListList expected_
 
 void
 ShowExtractorAsVariables(itkContourExtractor2DImageFilterTestNamespace::ExtractorType::Pointer extractor,
-                         std::string                                                           name)
+                         const std::string &                                                   name)
 {
   for (unsigned long i = 0; i < extractor->GetNumberOfIndexedOutputs(); ++i)
   {
diff --git a/Modules/IO/CSV/include/itkCSVFileReaderBase.h b/Modules/IO/CSV/include/itkCSVFileReaderBase.h
index 273e9a9c5d0..69dfd93aed9 100644
--- a/Modules/IO/CSV/include/itkCSVFileReaderBase.h
+++ b/Modules/IO/CSV/include/itkCSVFileReaderBase.h
@@ -140,7 +140,7 @@ class ITKIOCSV_EXPORT CSVFileReaderBase : public LightProcessObject
    */
   template <typename TData>
   TData
-  ConvertStringToValueType(const std::string str)
+  ConvertStringToValueType(const std::string & str)
   {
     TData              value;
     std::istringstream isstream(str);
diff --git a/Modules/IO/ImageBase/test/itkImageFileWriterStreamingPastingCompressingTest1.cxx b/Modules/IO/ImageBase/test/itkImageFileWriterStreamingPastingCompressingTest1.cxx
index f3ef5843e11..5254d4358de 100644
--- a/Modules/IO/ImageBase/test/itkImageFileWriterStreamingPastingCompressingTest1.cxx
+++ b/Modules/IO/ImageBase/test/itkImageFileWriterStreamingPastingCompressingTest1.cxx
@@ -87,9 +87,9 @@ SameImage(std::string testImageFileName, ImagePointer baselineImage)
 }
 
 bool
-ActualTest(std::string inputFileName,
-           std::string outputFileNameBase,
-           std::string outputFileNameExtension,
+ActualTest(const std::string & inputFileName,
+           const std::string & outputFileNameBase,
+           const std::string & outputFileNameExtension,
            bool        streamWriting,
            bool        pasteWriting,
            bool        compressWriting,
diff --git a/Modules/IO/Meta/test/testMetaImage.cxx b/Modules/IO/Meta/test/testMetaImage.cxx
index b00d96add69..c67124f3966 100644
--- a/Modules/IO/Meta/test/testMetaImage.cxx
+++ b/Modules/IO/Meta/test/testMetaImage.cxx
@@ -29,7 +29,7 @@
 
 template <typename PixelType, unsigned int Dimension>
 int
-ReadWriteCompare(PixelType value, std::string type)
+ReadWriteCompare(PixelType value, const std::string & type)
 {
   std::cout << "Testing: " << type << std::endl;
   using ImageType = itk::Image<PixelType, 3>;
diff --git a/Modules/IO/NRRD/test/itkNrrdImageIOTest.h b/Modules/IO/NRRD/test/itkNrrdImageIOTest.h
index 7062e0a3974..1a1a49e3730 100644
--- a/Modules/IO/NRRD/test/itkNrrdImageIOTest.h
+++ b/Modules/IO/NRRD/test/itkNrrdImageIOTest.h
@@ -57,7 +57,7 @@ itkNrrdImageIOTestGenerateRandomImage(unsigned int size)
 
 template <typename TPixelType, unsigned int VImageDimension>
 int
-itkNrrdImageIOTestReadWriteTest(std::string fn, unsigned int size, std::string inputFile, bool compression = false)
+itkNrrdImageIOTestReadWriteTest(const std::string & fn, unsigned int size, const std::string & inputFile, bool compression = false)
 {
   using ImageType = itk::Image<TPixelType, VImageDimension>;
 
diff --git a/Modules/IO/TIFF/test/itkTIFFImageIOTestPalette.cxx b/Modules/IO/TIFF/test/itkTIFFImageIOTestPalette.cxx
index 1e39bd97f22..8c913311a30 100644
--- a/Modules/IO/TIFF/test/itkTIFFImageIOTestPalette.cxx
+++ b/Modules/IO/TIFF/test/itkTIFFImageIOTestPalette.cxx
@@ -25,7 +25,7 @@
 
 template <typename T>
 void
-printPalette(std::vector<T> palette)
+printPalette(const std::vector<T> & palette)
 {
   for (unsigned int i = 0; i < palette.size(); ++i)
   {
diff --git a/Modules/IO/TransformHDF5/test/itkIOTransformHDF5Test.cxx b/Modules/IO/TransformHDF5/test/itkIOTransformHDF5Test.cxx
index 535441dafa3..29e24f139fe 100644
--- a/Modules/IO/TransformHDF5/test/itkIOTransformHDF5Test.cxx
+++ b/Modules/IO/TransformHDF5/test/itkIOTransformHDF5Test.cxx
@@ -39,7 +39,7 @@
 
 template <typename TParametersValueType, typename DisplacementTransformType>
 static int
-ReadWriteTest(const std::string fileName, const bool isRealDisplacementField, const bool useCompression)
+ReadWriteTest(const std::string & fileName, const bool isRealDisplacementField, const bool useCompression)
 {
   // First make a DisplacementField with known values
   constexpr double aNumberThatCanNotBeRepresentedInFloatingPoint = 1e-5 + 1e-7 + 1e-9 + 1e-13;
@@ -177,7 +177,7 @@ ReadWriteTest(const std::string fileName, const bool isRealDisplacementField, co
 
 template <typename TParametersValueType>
 static int
-oneTest(const std::string goodname, const std::string badname, const bool useCompression)
+oneTest(const std::string & goodname, const std::string badname, const bool useCompression)
 {
   using AffineTransformType = typename itk::AffineTransform<TParametersValueType, 4>;
   using AffineTransformTypeNotRegistered = typename itk::AffineTransform<TParametersValueType, 10>;
diff --git a/Modules/IO/VTK/test/itkVTKImageIO2Test.cxx b/Modules/IO/VTK/test/itkVTKImageIO2Test.cxx
index b05ceecd4e1..b9f675468c6 100644
--- a/Modules/IO/VTK/test/itkVTKImageIO2Test.cxx
+++ b/Modules/IO/VTK/test/itkVTKImageIO2Test.cxx
@@ -302,7 +302,7 @@ class VTKImageIOTester
 
 template <typename TScalar>
 int
-Test1AsciiBinary(std::string filePrefix, std::string outputPath, std::string typeName, bool ascii, bool read = true)
+Test1AsciiBinary(std::string filePrefix, std::string outputPath, const std::string & typeName, bool ascii, bool read = true)
 {
   std::string ab;
   if (ascii)
diff --git a/Modules/IO/VTK/test/itkVTKImageIOFileReadTest.cxx b/Modules/IO/VTK/test/itkVTKImageIOFileReadTest.cxx
index b333c37d1c5..df5c956e063 100644
--- a/Modules/IO/VTK/test/itkVTKImageIOFileReadTest.cxx
+++ b/Modules/IO/VTK/test/itkVTKImageIOFileReadTest.cxx
@@ -23,7 +23,7 @@
 
 template <class TImage>
 int
-ReadImage(const std::string fileName, typename TImage::Pointer image)
+ReadImage(const std::string & fileName, typename TImage::Pointer image)
 {
 
   using IOType = itk::VTKImageIO;
diff --git a/Modules/IO/XML/src/itkDOMNode.cxx b/Modules/IO/XML/src/itkDOMNode.cxx
index 9909365fc6d..5f48213ab3e 100644
--- a/Modules/IO/XML/src/itkDOMNode.cxx
+++ b/Modules/IO/XML/src/itkDOMNode.cxx
@@ -569,7 +569,7 @@ DOMNode::Find(const std::string & path)
     if (pos != std::string::npos)
     {
       const std::string s2 = s.substr(pos + 1);
-      s = s.substr(0, pos);
+      s.resize(pos);
       std::istringstream iss(s2);
       IdentifierType     i = 0;
       iss >> i;
diff --git a/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationOnVectorTest.cxx b/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationOnVectorTest.cxx
index f94c30c03e4..5cf0da05df1 100644
--- a/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationOnVectorTest.cxx
+++ b/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationOnVectorTest.cxx
@@ -37,7 +37,7 @@ template <typename TMovingTransform>
 int
 itkAutoScaledGradientDescentRegistrationOnVectorTestTemplated(int         numberOfIterations,
                                                               double      shiftOfStep,
-                                                              std::string scalesOption)
+                                                              const std::string & scalesOption)
 {
   const unsigned int Dimension = TMovingTransform::SpaceDimension;
 
diff --git a/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationTest.cxx b/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationTest.cxx
index 5a891c9f964..29320a34d67 100644
--- a/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationTest.cxx
+++ b/Modules/Numerics/Optimizersv4/test/itkAutoScaledGradientDescentRegistrationTest.cxx
@@ -37,7 +37,7 @@ template <typename TMovingTransform>
 int
 itkAutoScaledGradientDescentRegistrationTestTemplated(int         numberOfIterations,
                                                       double      shiftOfStep,
-                                                      std::string scalesOption,
+                                                      const std::string & scalesOption,
                                                       bool        usePhysicalSpaceForShift,
                                                       bool        estimateLearningRateOnce,
                                                       bool        estimateLearningRateAtEachIteration,
diff --git a/Modules/Numerics/Optimizersv4/test/itkQuasiNewtonOptimizerv4Test.cxx b/Modules/Numerics/Optimizersv4/test/itkQuasiNewtonOptimizerv4Test.cxx
index 388916b8b3c..40be8f93e70 100644
--- a/Modules/Numerics/Optimizersv4/test/itkQuasiNewtonOptimizerv4Test.cxx
+++ b/Modules/Numerics/Optimizersv4/test/itkQuasiNewtonOptimizerv4Test.cxx
@@ -39,7 +39,7 @@ template <typename TMovingTransform>
 int
 itkQuasiNewtonOptimizerv4TestTemplated(int         numberOfIterations,
                                        double      shiftOfStep,
-                                       std::string scalesOption,
+                                       const std::string & scalesOption,
                                        bool        usePhysicalSpaceForShift = true)
 {
   const unsigned int Dimension = TMovingTransform::SpaceDimension;
diff --git a/Modules/Segmentation/ConnectedComponents/test/itkHardConnectedComponentImageFilterTest.cxx b/Modules/Segmentation/ConnectedComponents/test/itkHardConnectedComponentImageFilterTest.cxx
index 00213306b11..113350110d3 100644
--- a/Modules/Segmentation/ConnectedComponents/test/itkHardConnectedComponentImageFilterTest.cxx
+++ b/Modules/Segmentation/ConnectedComponents/test/itkHardConnectedComponentImageFilterTest.cxx
@@ -23,7 +23,7 @@
 
 template <typename TPixel>
 int
-DoIt(int argc, char * argv[], const std::string pixelType)
+DoIt(int argc, char * argv[], const std::string & pixelType)
 {
   if (argc < 2)
   {