diff --git a/PHPSkills/FactorGraphs/VariableFactory.php b/PHPSkills/FactorGraphs/VariableFactory.php
index 79226ab..74cb315 100644
--- a/PHPSkills/FactorGraphs/VariableFactory.php
+++ b/PHPSkills/FactorGraphs/VariableFactory.php
@@ -16,7 +16,8 @@ class VariableFactory
 
     public function createBasicVariable()
     {
-        $newVar = new Variable($this->_variablePriorInitializer());
+        $initializer = $this->_variablePriorInitializer;
+        $newVar = new Variable("variable", $initializer());
         return $newVar;
     }
 
diff --git a/PHPSkills/PartialPlay.php b/PHPSkills/PartialPlay.php
index c1d6c73..4d193e7 100644
--- a/PHPSkills/PartialPlay.php
+++ b/PHPSkills/PartialPlay.php
@@ -14,7 +14,7 @@ class PartialPlay
             return 1.0;
         }
 
-        $partialPlayPercentage = $partialPlay->getPartialPlayPercentage();
+        $partialPlayPercentage = $player->getPartialPlayPercentage();
 
         // HACK to get around bug near 0
         $smallestPercentage = 0.0001;
diff --git a/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php b/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
index 30578ae..3f50550 100644
--- a/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
+++ b/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
@@ -1,15 +1,19 @@
 <?php
 namespace Moserware\Skills\TrueSkill\Layers;
 
+require_once(dirname(__FILE__) . "/../../PartialPlay.php");
 require_once(dirname(__FILE__) . "/../../FactorGraphs/Schedule.php");
+require_once(dirname(__FILE__) . "/../Factors/GaussianWeightedSumFactor.php");
 require_once(dirname(__FILE__) . "/../TrueSkillFactorGraph.php");
 require_once(dirname(__FILE__) . "/TrueSkillFactorGraphLayer.php");
 require_once(dirname(__FILE__) . "/TeamPerformancesToTeamPerformanceDifferencesLayer.php");
 require_once(dirname(__FILE__) . "/TeamDifferencesComparisonLayer.php");
 
+use Moserware\Skills\PartialPlay;
 use Moserware\Skills\FactorGraphs\ScheduleLoop;
 use Moserware\Skills\FactorGraphs\ScheduleSequence;
 use Moserware\Skills\FactorGraphs\ScheduleStep;
+use Moserware\Skills\TrueSkill\Factors\GaussianWeightedSumFactor;
 use Moserware\Skills\TrueSkill\TrueSkillFactorGraph;
 
 class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLayer
@@ -46,15 +50,17 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
 
     protected function createPlayerToTeamSumFactor(&$teamMembers, &$sumVariable)
     {
-        return new GaussianWeightedSumFactor(
-                $sumVariable,
-                $teamMembers,
-                array_map(
+        $weights = array_map(
                         function($v)
                         {
                             return PartialPlay::getPartialPlayPercentage($v->getKey());
                         },
-                        $teamMembers));
+                        $teamMembers);
+
+        return new GaussianWeightedSumFactor(
+                $sumVariable,
+                $teamMembers,
+                $weights);
                                                  
     }
 
diff --git a/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php b/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
index 6318d46..261fd2b 100644
--- a/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
+++ b/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
@@ -28,11 +28,11 @@ class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
             {
                 $playerPerformance = $this->createOutputVariable($playerSkillVariable->getKey());
                 $this->addLayerFactor($this->createLikelihood($playerSkillVariable, $playerPerformance));
-                $currentTeamPlayerPerformances[] = $playerPerformance;
+                $currentTeamPlayerPerformances[] = &$playerPerformance;
             }
             
-            $outputVariablesGroups = $this->getOutputVariablesGroups();
-            $outputVariablesGroups[] = $currentTeamPlayerPerformances;
+            $outputVariablesGroups = &$this->getOutputVariablesGroups();
+            $outputVariablesGroups[] = &$currentTeamPlayerPerformances;
         }
     }
 
diff --git a/PHPSkills/TrueSkill/TrueSkillFactorGraph.php b/PHPSkills/TrueSkill/TrueSkillFactorGraph.php
index f484aea..640c23c 100644
--- a/PHPSkills/TrueSkill/TrueSkillFactorGraph.php
+++ b/PHPSkills/TrueSkill/TrueSkillFactorGraph.php
@@ -75,7 +75,7 @@ class TrueSkillFactorGraph extends FactorGraph
 
             $currentLayer->buildLayer();
 
-            $lastOutput = $currentLayer->getOutputVariablesGroups();
+            $lastOutput = &$currentLayer->getOutputVariablesGroups();
         }
     }