diff --git a/lib/qme/map/map_reduce_executor.rb b/lib/qme/map/map_reduce_executor.rb
index 9ca138a..b75c30e 100644
--- a/lib/qme/map/map_reduce_executor.rb
+++ b/lib/qme/map/map_reduce_executor.rb
@@ -35,10 +35,11 @@ def build_query
         filters = @parameter_values["filters"]
 
 
-        match = {'value.measure_id' => @measure_id,
+        match = {'value.measure_id'       => @measure_id,
                  'value.sub_id'           => @sub_id,
                  'value.effective_date'   => @parameter_values['effective_date'],
                  'value.test_id'          => @parameter_values['test_id'],
+                 'value.expired_at'       => nil,
                  'value.manual_exclusion' => {'$in' => [nil, false]}}
 
         if(filters)
@@ -90,7 +91,7 @@ def calculate_supplemental_data_elements
         supplemental_data = Hash[*keys.map{|k| [k,{QME::QualityReport::RACE => {},
                                                    QME::QualityReport::ETHNICITY => {},
                                                    QME::QualityReport::SEX => {},
-                                                   QME::QualityReport::PAYER => {}}]}.flatten]                                      
+                                                   QME::QualityReport::PAYER => {}}]}.flatten]
         keys.each do |pop_id|
           pline = build_query
 
diff --git a/lib/qme/map/measure_calculation_job.rb b/lib/qme/map/measure_calculation_job.rb
index 6f41439..8a99145 100644
--- a/lib/qme/map/measure_calculation_job.rb
+++ b/lib/qme/map/measure_calculation_job.rb
@@ -19,9 +19,10 @@ def initialize(options)
       end
 
       def perform
-        if !@quality_report.calculated?
+        if !@quality_report.calculated? || @options['recalculate']
           map = QME::MapReduce::Executor.new(@quality_report.measure_id,@quality_report.sub_id, @options.merge('start_time' => Time.now.to_i))
-          if !@quality_report.patients_cached?
+          if !@quality_report.patients_cached? || @options['recalculate']
+            @quality_report.expire_patient_results
             tick('Starting MapReduce')
             map.map_records_into_measure_groups(@options['prefilter'])
             tick('MapReduce complete')
diff --git a/lib/qme/quality_report.rb b/lib/qme/quality_report.rb
index c318b50..cc19449 100644
--- a/lib/qme/quality_report.rb
+++ b/lib/qme/quality_report.rb
@@ -166,6 +166,10 @@ def patient_results
      QME::PatientCache.where(patient_cache_matcher)
     end
 
+    def expire_patient_results
+      patient_results.update_all("value.expired_at" => Time.now)
+    end
+
     def measure
       QME::QualityMeasure.where({"hqmf_id"=>self.measure_id, "sub_id" => self.sub_id}).first
     end
@@ -189,6 +193,7 @@ def patient_cache_matcher
                'value.sub_id'           => self.sub_id,
                'value.effective_date'   => self.effective_date,
                'value.test_id'          => test_id,
+               'value.expired_at'       => nil,
                'value.manual_exclusion' => {'$in' => [nil, false]}}
 
       if(filters)
diff --git a/test/unit/qme/map/measure_calculation_job_test.rb b/test/unit/qme/map/measure_calculation_job_test.rb
index 2d96804..945bcc1 100644
--- a/test/unit/qme/map/measure_calculation_job_test.rb
+++ b/test/unit/qme/map/measure_calculation_job_test.rb
@@ -21,4 +21,51 @@ def test_perform
     job = Delayed::Job.enqueue(QME::MapReduce::MeasureCalculationJob.new({'quality_report_id' => qr.id,"oid_dictionary"=>{}}))
     assert job
   end
-end
\ No newline at end of file
+
+  def test_perform_recalculate
+    options = {
+      'measure_id' => '2E679CD2-3FEC-4A75-A75A-61403E5EFEE8',
+      'effective_date' => Time.gm(2011, 1, 15).to_i,
+    }
+
+    qr = QME::QualityReport.find_or_create_by(options)
+    job = QME::MapReduce::MeasureCalculationJob.new(
+      {
+        'quality_report_id' => qr.id,
+        'oid_dictionary' => {},
+        'recalculate' => true
+      }
+    )
+    job.perform
+    job.perform # Perform second time to expire the originals
+
+    assert_equal 4, qr.patient_results.count
+    assert_equal(
+      4, QME::PatientCache.where(:'value.expired_at'.exists => true).count
+    )
+  end
+
+  def test_perform_no_recalculate
+    options = {
+      'measure_id' => '2E679CD2-3FEC-4A75-A75A-61403E5EFEE8',
+      'effective_date' => Time.gm(2011, 1, 15).to_i,
+      'status.state' => 'complete'
+    }
+
+    qr = QME::QualityReport.find_or_create_by(options)
+    job = QME::MapReduce::MeasureCalculationJob.new(
+      {
+        'quality_report_id' => qr.id,
+        'oid_dictionary' => {},
+        'recalculate' => false
+      }
+    )
+    job.perform
+    job.perform
+
+    assert_equal 4, qr.patient_results.count
+    assert_equal(
+      0, QME::PatientCache.where(:'value.expired_at'.exists => true).count
+    )
+  end
+end
diff --git a/test/unit/qme/quality_report_test.rb b/test/unit/qme/quality_report_test.rb
index d4f8f22..fc9ee75 100644
--- a/test/unit/qme/quality_report_test.rb
+++ b/test/unit/qme/quality_report_test.rb
@@ -45,7 +45,8 @@ def setup
             },
             "measure_id" => "test2",
             "sub_id" =>  "b",
-            "effective_date" => Time.gm(2010, 9, 19).to_i
+            "effective_date" => Time.gm(2010, 9, 19).to_i,
+            "expired_at" => nil
           }}
     )
     collection_fixtures(get_db(), 'delayed_backend_mongoid_jobs', '_id')
@@ -129,4 +130,42 @@ def test_rollup_buffering
 
     assert_equal 0, Mongoid.default_client["rollup_buffer"].count({})
   end
+
+  def test_expire_patient_results
+    qr = QME::QualityReport.find_or_create(
+      'test2',
+      'b',
+      'effective_date' => Time.gm(2010, 9, 19).to_i
+    )
+
+
+    assert_equal 1, qr.patient_results.count
+
+    qr.expire_patient_results
+
+    assert_equal 0, qr.patient_results.count
+  end
+
+  def test_patient_cache_matcher
+    effective_date = Time.gm(2010, 9, 19).to_i
+    qr = QME::QualityReport.find_or_create(
+      'test2',
+      'b',
+      'effective_date' => effective_date
+    )
+
+    expected_results = {
+      'value.measure_id' => 'test2',
+      'value.sub_id' => 'b',
+      'value.effective_date' => effective_date,
+      'value.test_id' => nil,
+      'value.facility_id' => nil,
+      'value.expired_at' => nil,
+      'value.manual_exclusion' => {
+        '$in' => [nil, false]
+      }
+    }
+
+    assert_equal expected_results, qr.patient_cache_matcher
+  end
 end