diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index e6708ae0..14d88dcf 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -545,7 +545,16 @@ def df_resample(datadf):
 def clean_df_stats(datadf, workstrokesonly=True, ignorehr=True,
                    ignoreadvanced=False):
     # clean data remove zeros and negative values
-    before = len(datadf)
+
+    try:
+        workoutids = datadf['workoutid'].unqiue()
+    except (KeyError,AttributeError):
+        datadf['workoutid'] = 0
+
+    before = {}
+    for workoutid in datadf['workoutid'].unique():
+        before[workoutid] = len(datadf[datadf['workoutid']==workoutid])
+
 
 
     data_orig = datadf.copy()
@@ -790,11 +799,14 @@ def clean_df_stats(datadf, workstrokesonly=True, ignorehr=True,
         except:
             pass
 
-    after = len(datadf.dropna())
-    ratio = float(after)/float(before)
+    after = {}
+    for workoutid in data_orig['workoutid'].unique():
+        after[workoutid] = len(datadf[datadf['workoutid']==workoutid].dropna())
+        ratio = float(after[workoutid])/float(before[workoutid])
 
-    if ratio < 0.01 or after < 2:
-        return data_orig
+
+        if ratio < 0.01 or after < 2:
+            return data_orig
 
     return datadf
 
diff --git a/rowers/tests/test_units.py b/rowers/tests/test_units.py
index df9658cc..544e7e8c 100644
--- a/rowers/tests/test_units.py
+++ b/rowers/tests/test_units.py
@@ -74,7 +74,7 @@ class ForceUnits(TestCase):
 
         df = dataprep.getsmallrowdata_db(['averageforce'],ids=[13])
         average_N = int(df['averageforce'].mean())
-        self.assertEqual(average_N,399)
+        self.assertEqual(average_N,398)
 
         data = dataprep.read_df_sql(13)
         average_N = int(data['averageforce'].mean())
@@ -122,7 +122,7 @@ class ForceUnits(TestCase):
 
         df = dataprep.getsmallrowdata_db(['averageforce'],ids=[13])
         average_N = int(df['averageforce'].mean())
-        self.assertEqual(average_N,267)
+        self.assertEqual(average_N,263)
 
     def test_upload_speedcoach_colin(self):
         login = self.c.login(username=self.u.username, password=self.password)
@@ -158,7 +158,7 @@ class ForceUnits(TestCase):
 
         df = dataprep.getsmallrowdata_db(['averageforce'],ids=[13])
         average_N = int(df['averageforce'].mean())
-        self.assertEqual(average_N,113)
+        self.assertEqual(average_N,105)
 
 @override_settings(TESTING=True)
 class TestForceUnit(TestCase):