diff --git a/src/Athlete.cpp b/src/Athlete.cpp
index 15387799d..b6b357a5b 100644
--- a/src/Athlete.cpp
+++ b/src/Athlete.cpp
@@ -541,3 +541,22 @@ Athlete::getPMCFor(QString metricName, int stsdays, int ltsdays)
 
     return returning;
 }
+
+PMCData *
+Athlete::getPMCFor(Leaf *expr, DataFilter *df, int stsdays, int ltsdays)
+{
+    PMCData *returning = NULL;
+
+    // if we don't already have one, create it
+    returning = pmcData.value(expr->signature(), NULL);
+    if (!returning) {
+
+        // specification is blank and passes for all
+        returning = new PMCData(context, Specification(), expr, df, stsdays, ltsdays);
+
+        // add to our collection
+        pmcData.insert(expr->signature(), returning);
+    }
+
+    return returning;
+}
diff --git a/src/Athlete.h b/src/Athlete.h
index fc9a62aba..733494c6d 100644
--- a/src/Athlete.h
+++ b/src/Athlete.h
@@ -58,6 +58,8 @@ class Context;
 class ColorEngine;
 class AnalysisSidebar;
 class Tab;
+class Leaf;
+class DataFilter;
 
 class Athlete : public QObject
 {
@@ -97,6 +99,7 @@ class Athlete : public QObject
 
         // PMC Data
         PMCData *getPMCFor(QString metricName, int stsDays = -1, int ltsDays = -1); // no Specification used!
+        PMCData *getPMCFor(Leaf *expr, DataFilter *df, int stsDays = -1, int ltsDays = -1); // no Specification used!
         QMap<QString, PMCData*> pmcData; // all the different PMC series
 
         // athlete measures
diff --git a/src/PMCData.cpp b/src/PMCData.cpp
index 319e2ff3c..9d5899615 100644
--- a/src/PMCData.cpp
+++ b/src/PMCData.cpp
@@ -42,6 +42,7 @@ PMCData::PMCData(Context *context, Specification spec, QString metricName, int s
     // we're not from a datafilter
     fromDataFilter = false;
     df = NULL;
+    expr = NULL;
 
     if (ltsDays < 0) {
         QVariant lts = appsettings->cvalue(context->athlete->cyclist, GC_LTS_DAYS);
@@ -63,17 +64,16 @@ PMCData::PMCData(Context *context, Specification spec, QString metricName, int s
     connect(context, SIGNAL(refreshUpdate(QDate)), this, SLOT(invalidate()));
 }
 
-PMCData::PMCData(Context *context, Specification spec, DataFilter *df, int stsDays, int ltsDays) 
+PMCData::PMCData(Context *context, Specification spec, Leaf *expr, DataFilter *df, int stsDays, int ltsDays) 
     : context(context), specification_(spec), metricName_(""), stsDays_(stsDays), ltsDays_(ltsDays), isstale(true)
 {
     // get defaults if not passed
     useDefaults = false;
+
+    // use an expression
     fromDataFilter = true;
     this->df = df;
-
-    // we're not from a datafilter
-    fromDataFilter = false;
-    df = NULL;
+    this->expr = expr;
 
     if (ltsDays < 0) {
         QVariant lts = appsettings->cvalue(context->athlete->cyclist, GC_LTS_DAYS);
@@ -216,7 +216,7 @@ void PMCData::refresh()
             // although metrics are cleansed, we check here because development
             // builds have a rideDB.json that has nan and inf values in it.
             double value = 0;;
-            if (fromDataFilter) value = df->evaluate(item).number;
+            if (fromDataFilter) value = expr->eval(context, df, expr, item).number;
             else value = item->getForSymbol(metricName_);
 
             if (!std::isinf(value) && !std::isnan(value))
diff --git a/src/PMCData.h b/src/PMCData.h
index a37c3b473..b604f1206 100644
--- a/src/PMCData.h
+++ b/src/PMCData.h
@@ -42,7 +42,7 @@ class PMCData : public QObject {
         // create a PMC data series for the athlete
         // for ALL date ranges
         PMCData(Context *, Specification specification, QString metricName, int stsDays=-1, int ltsDays=-1);
-        PMCData(Context *, Specification specification, DataFilter *df, int stsDays=-1, int ltsDays=-1);
+        PMCData(Context *, Specification specification, Leaf *expr, DataFilter *df, int stsDays=-1, int ltsDays=-1);
 
         // set parameters
         void setStsDays(int x) { stsDays_ = x; invalidate(); }
@@ -99,6 +99,7 @@ class PMCData : public QObject {
 
         bool fromDataFilter;
         DataFilter *df;
+        Leaf *expr;
 
         // parameters
         QString metricName_;