diff --git a/openbr/plugins/cluster.cpp b/openbr/plugins/cluster.cpp
index 14cdb03..3a9b577 100644
--- a/openbr/plugins/cluster.cpp
+++ b/openbr/plugins/cluster.cpp
@@ -90,11 +90,13 @@ class KNNTransform : public Transform
     Q_PROPERTY(bool weighted READ get_weighted WRITE set_weighted RESET reset_weighted STORED false)
     Q_PROPERTY(int numSubjects READ get_numSubjects WRITE set_numSubjects RESET reset_numSubjects STORED false)
     Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
+    Q_PROPERTY(QString outputVariable READ get_outputVariable WRITE set_outputVariable RESET reset_outputVariable STORED false)
     BR_PROPERTY(int, k, 1)
     BR_PROPERTY(br::Distance*, distance, NULL)
     BR_PROPERTY(bool, weighted, false)
     BR_PROPERTY(int, numSubjects, 1)
     BR_PROPERTY(QString, inputVariable, "Label")
+    BR_PROPERTY(QString, outputVariable, "KNN")
 
     TemplateList gallery;
 
@@ -123,7 +125,7 @@ class KNNTransform : public Transform
                         sortedScores.removeAt(j);
         }
 
-        dst.file.set("KNN", subjects.size() > 1 ? "[" + subjects.join(",") + "]" : subjects.first());
+        dst.file.set(outputVariable, subjects.size() > 1 ? "[" + subjects.join(",") + "]" : subjects.first());
     }
 
     void store(QDataStream &stream) const
diff --git a/openbr/plugins/independent.cpp b/openbr/plugins/independent.cpp
index e220d74..00770bf 100644
--- a/openbr/plugins/independent.cpp
+++ b/openbr/plugins/independent.cpp
@@ -9,7 +9,7 @@ using namespace cv;
 namespace br
 {
 
-static TemplateList Downsample(const TemplateList &templates, const Transform *transform)
+static TemplateList Downsample(const TemplateList &templates, const Transform *transform, const QString & inputVariable)
 {
     // Return early when no downsampling is required
     if ((transform->classes == std::numeric_limits<int>::max()) &&
@@ -20,11 +20,11 @@ static TemplateList Downsample(const TemplateList &templates, const Transform *t
     const bool atLeast = transform->instances < 0;
     const int instances = abs(transform->instances);
 
-    QList<QString> allLabels = templates.get<QString>("Label");
+    QList<QString> allLabels = templates.get<QString>(inputVariable);
     QList<QString> uniqueLabels = allLabels.toSet().toList();
     qSort(uniqueLabels);
 
-    QMap<QString,int> counts = templates.countValues<QString>("Label", instances != std::numeric_limits<int>::max());
+    QMap<QString,int> counts = templates.countValues<QString>(inputVariable, instances != std::numeric_limits<int>::max());
 
     if ((instances != std::numeric_limits<int>::max()) && (transform->classes != std::numeric_limits<int>::max()))
         foreach (const QString & label, counts.keys())
@@ -74,7 +74,9 @@ class IndependentTransform : public MetaTransform
 {
     Q_OBJECT
     Q_PROPERTY(br::Transform* transform READ get_transform WRITE set_transform RESET reset_transform STORED false)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
     BR_PROPERTY(br::Transform*, transform, NULL)
+    BR_PROPERTY(QString, inputVariable, "Label")
 
     QList<Transform*> transforms;
 
@@ -123,7 +125,7 @@ class IndependentTransform : public MetaTransform
             transforms.append(transform->clone());
 
         for (int i=0; i<templatesList.size(); i++)
-            templatesList[i] = Downsample(templatesList[i], transforms[i]);
+            templatesList[i] = Downsample(templatesList[i], transforms[i], inputVariable);
 
         QFutureSynchronizer<void> futures;
         for (int i=0; i<templatesList.size(); i++)
diff --git a/openbr/plugins/normalize.cpp b/openbr/plugins/normalize.cpp
index f97a162..842e952 100644
--- a/openbr/plugins/normalize.cpp
+++ b/openbr/plugins/normalize.cpp
@@ -97,6 +97,7 @@ class CenterTransform : public Transform
     Q_OBJECT
     Q_ENUMS(Method)
     Q_PROPERTY(Method method READ get_method WRITE set_method RESET reset_method STORED false)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
 
 public:
     /*!< */
@@ -107,6 +108,7 @@ public:
 
 private:
     BR_PROPERTY(Method, method, Mean)
+    BR_PROPERTY(QString, inputVariable, "Label")
 
     Mat a, b; // dst = (src - b) / a
 
@@ -127,7 +129,7 @@ private:
         Mat m;
         OpenCVUtils::toMat(data.data()).convertTo(m, CV_64F);
 
-        const QList<int> labels = data.indexProperty("Label");
+        const QList<int> labels = data.indexProperty(inputVariable);
         const int dims = m.cols;
 
         vector<Mat> mv, av, bv;
diff --git a/openbr/plugins/quality.cpp b/openbr/plugins/quality.cpp
index 972fecb..468ef5e 100644
--- a/openbr/plugins/quality.cpp
+++ b/openbr/plugins/quality.cpp
@@ -19,17 +19,20 @@ class ImpostorUniquenessMeasureTransform : public Transform
     Q_PROPERTY(br::Distance* distance READ get_distance WRITE set_distance RESET reset_distance STORED false)
     Q_PROPERTY(double mean READ get_mean WRITE set_mean RESET reset_mean)
     Q_PROPERTY(double stddev READ get_stddev WRITE set_stddev RESET reset_stddev)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
     BR_PROPERTY(br::Distance*, distance, Distance::make("Dist(L2)", this))
     BR_PROPERTY(double, mean, 0)
     BR_PROPERTY(double, stddev, 1)
+    BR_PROPERTY(QString, inputVariable, "Label")
+
     TemplateList impostors;
 
     float calculateIUM(const Template &probe, const TemplateList &gallery) const
     {
-        const QString probeLabel = probe.file.get<QString>("Label");
+        const QString probeLabel = probe.file.get<QString>(inputVariable);
         TemplateList subset = gallery;
         for (int j=subset.size()-1; j>=0; j--)
-            if (subset[j].file.get<QString>("Label") == probeLabel)
+            if (subset[j].file.get<QString>(inputVariable) == probeLabel)
                 subset.removeAt(j);
 
         QList<float> scores = distance->compare(subset, probe);
@@ -151,6 +154,7 @@ class MatchProbabilityDistance : public Distance
     Q_PROPERTY(br::Distance* distance READ get_distance WRITE set_distance RESET reset_distance STORED false)
     Q_PROPERTY(bool gaussian READ get_gaussian WRITE set_gaussian RESET reset_gaussian STORED false)
     Q_PROPERTY(bool crossModality READ get_crossModality WRITE set_crossModality RESET reset_crossModality STORED false)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
 
     MP mp;
 
@@ -158,7 +162,7 @@ class MatchProbabilityDistance : public Distance
     {
         distance->train(src);
 
-        const QList<int> labels = src.indexProperty("Label");
+        const QList<int> labels = src.indexProperty(inputVariable);
         QScopedPointer<MatrixOutput> matrixOutput(MatrixOutput::make(FileList(src.size()), FileList(src.size())));
         distance->compare(src, src, matrixOutput.data());
 
@@ -201,6 +205,7 @@ protected:
     BR_PROPERTY(br::Distance*, distance, make("Dist(L2)"))
     BR_PROPERTY(bool, gaussian, true)
     BR_PROPERTY(bool, crossModality, false)
+    BR_PROPERTY(QString, inputVariable, "Label")
 };
 
 BR_REGISTER(Distance, MatchProbabilityDistance)
@@ -217,10 +222,12 @@ class HeatMapDistance : public Distance
     Q_PROPERTY(bool gaussian READ get_gaussian WRITE set_gaussian RESET reset_gaussian STORED false)
     Q_PROPERTY(bool crossModality READ get_crossModality WRITE set_crossModality RESET reset_crossModality STORED false)
     Q_PROPERTY(int step READ get_step WRITE set_step RESET reset_step STORED false)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
     BR_PROPERTY(br::Distance*, distance, make("Dist(L2)"))
     BR_PROPERTY(bool, gaussian, true)
     BR_PROPERTY(bool, crossModality, false)
     BR_PROPERTY(int, step, 1)
+    BR_PROPERTY(QString, inputVariable, "Label")
 
     QList<MP> mp;
 
@@ -228,7 +235,7 @@ class HeatMapDistance : public Distance
     {
         distance->train(src);
 
-        const QList<int> labels = src.indexProperty("Label");
+        const QList<int> labels = src.indexProperty(inputVariable);
 
         QList<TemplateList> patches;
 
@@ -309,14 +316,16 @@ class UnitDistance : public Distance
     Q_PROPERTY(br::Distance *distance READ get_distance WRITE set_distance RESET reset_distance)
     Q_PROPERTY(float a READ get_a WRITE set_a RESET reset_a)
     Q_PROPERTY(float b READ get_b WRITE set_b RESET reset_b)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
     BR_PROPERTY(br::Distance*, distance, make("Dist(L2)"))
     BR_PROPERTY(float, a, 1)
     BR_PROPERTY(float, b, 0)
+    BR_PROPERTY(QString, inputVariable, "Label")
 
     void train(const TemplateList &templates)
     {
         const TemplateList samples = templates.mid(0, 2000);
-        const QList<int> sampleLabels = samples.indexProperty("Label");
+        const QList<int> sampleLabels = samples.indexProperty(inputVariable);
         QScopedPointer<MatrixOutput> matrixOutput(MatrixOutput::make(FileList(samples.size()), FileList(samples.size())));
         Distance::compare(samples, samples, matrixOutput.data());
 
diff --git a/openbr/plugins/quantize.cpp b/openbr/plugins/quantize.cpp
index 163da7f..e74513f 100644
--- a/openbr/plugins/quantize.cpp
+++ b/openbr/plugins/quantize.cpp
@@ -120,6 +120,10 @@ BR_REGISTER(Transform, HistEqQuantizationTransform)
 class BayesianQuantizationDistance : public Distance
 {
     Q_OBJECT
+
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
+    BR_PROPERTY(QString, inputVariable, "Label")
+
     QVector<float> loglikelihoods;
 
     static void computeLogLikelihood(const Mat &data, const QList<int> &labels, float *loglikelihood)
@@ -150,7 +154,7 @@ class BayesianQuantizationDistance : public Distance
             qFatal("Expected sigle matrix templates of type CV_8UC1!");
 
         const Mat data = OpenCVUtils::toMat(src.data());
-        const QList<int> templateLabels = src.indexProperty("Label");
+        const QList<int> templateLabels = src.indexProperty(inputVariable);
         loglikelihoods = QVector<float>(data.cols*256, 0);
 
         QFutureSynchronizer<void> futures;
@@ -343,9 +347,11 @@ class ProductQuantizationTransform : public Transform
     Q_PROPERTY(int n READ get_n WRITE set_n RESET reset_n STORED false)
     Q_PROPERTY(br::Distance *distance READ get_distance WRITE set_distance RESET reset_distance STORED false)
     Q_PROPERTY(bool bayesian READ get_bayesian WRITE set_bayesian RESET reset_bayesian STORED false)
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
     BR_PROPERTY(int, n, 2)
     BR_PROPERTY(br::Distance*, distance, Distance::make("L2", this))
     BR_PROPERTY(bool, bayesian, false)
+    BR_PROPERTY(QString, inputVariable, "Label")
 
     quint16 index;
     QList<Mat> centers;
@@ -474,7 +480,7 @@ private:
         Mat data = OpenCVUtils::toMat(src.data());
         const int step = getStep(data.cols);
 
-        const QList<int> labels = src.indexProperty("Label");
+        const QList<int> labels = src.indexProperty(inputVariable);
 
         Mat &lut = ProductQuantizationLUTs[index];
         lut = Mat(getDims(data.cols), 256*(256+1)/2, CV_32FC1);
diff --git a/openbr/plugins/quantize2.cpp b/openbr/plugins/quantize2.cpp
index d46db1e..8d05523 100644
--- a/openbr/plugins/quantize2.cpp
+++ b/openbr/plugins/quantize2.cpp
@@ -19,6 +19,10 @@ namespace br
 class BayesianQuantizationTransform : public Transform
 {
     Q_OBJECT
+
+    Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
+    BR_PROPERTY(QString, inputVariable, "Label")
+
     QVector<float> thresholds;
 
     static void computeThresholdsRecursive(const QVector<int> &cumulativeGenuines, const QVector<int> &cumulativeImpostors,
@@ -77,7 +81,7 @@ class BayesianQuantizationTransform : public Transform
     void train(const TemplateList &src)
     {
         const Mat data = OpenCVUtils::toMat(src.data());
-        const QList<int> labels = src.indexProperty("Label");
+        const QList<int> labels = src.indexProperty(inputVariable);
 
         thresholds = QVector<float>(256*data.cols);