diff --git a/lib/WebGUI/Asset/Wobject/Survey/ExpressionEngine.pm b/lib/WebGUI/Asset/Wobject/Survey/ExpressionEngine.pm
index 03e57c198..447343d92 100644
--- a/lib/WebGUI/Asset/Wobject/Survey/ExpressionEngine.pm
+++ b/lib/WebGUI/Asset/Wobject/Survey/ExpressionEngine.pm
@@ -8,6 +8,10 @@ Package WebGUI::Asset::Wobject::Survey::ExpressionEngine
 
 This class is used to process Survey gotoExpressions.
 
+If you want to allow the expression engine to run you need to turn on the enableSurveyExpressionEngine flag
+in your site config file. This is because no matter how 'Safe' the Safe.pm compartment is, it still has
+caveats. For example, it doesn't protect you from infinite loops.  
+
 See L<run> for more details.
 
 =cut
@@ -17,6 +21,7 @@ use Params::Validate qw(:all);
 use Safe;
 use Data::Dumper;
 use List::Util qw/sum/;
+use WebGUI::Asset;
 Params::Validate::validation_options( on_fail => sub { WebGUI::Error::InvalidParam->throw( error => shift ) } );
 
 # We need these as semi-globals so that utility subs (which are shared with the safe compartment)
@@ -27,20 +32,39 @@ my $scores;
 my $jump_count;
 my $validate;
 my $validTargets;
- 
+my $other_instances;
+
 =head2 value
 
 Utility sub that gives expressions access to recorded response values
 
 value(question_variable) returns the recorded response value for the answer to question_variable
 
+value(asset_spec, question_variable) returns value(question_variable) on the most recent completed response
+ for the user on the survey instance given by asset_spec (either an assetId or a url)
+
 =cut
 
-sub value($) {
+sub value {
+    # Two arguments implies the first arg is an asset_spec
+    if ( @_ == 2 ) {
+        my ( $asset_spec, $key ) = @_;
+        
+        # See if $other_instances already contains the external survey
+        if (my $other_instance = $other_instances->{$asset_spec}) {
+            my $values = $other_instance->{values};
+            my $value  = $values->{$key};
+            $session->log->debug("[$asset_spec, $key] resolves to [$value]");
+            return $value;
+        } else {
+            # Throw an exception, triggering run() to resolve the external reference and re-run
+            die( { other_instance => $asset_spec } );
+        }
+    }
     my $key   = shift;
     my $value = $values->{$key};
     $session->log->debug("[$key] resolves to [$value]");
-    return $value; # scalar variable, so no need to clone
+    return $value;    # scalar variable, so no need to clone
 }
 
 =head2 score
@@ -52,11 +76,26 @@ score(section_variable) returns the summed score for the answers to all the ques
 
 =cut
 
-sub score($) {
+sub score {
+    # Two arguments implies the first arg is an asset_spec
+    if ( @_ == 2 ) {
+        my ( $asset_spec, $key ) = @_;
+        
+        # See if $other_instances already contains the external survey
+        if (my $other_instance = $other_instances->{$asset_spec}) {
+            my $scores = $other_instance->{scores};
+            my $score  = $scores->{$key};
+            $session->log->debug("[$asset_spec, $key] resolves to [$score]");
+            return $score;
+        } else {
+            # Throw an exception, triggering run() to resolve the external reference and re-run
+            die( { other_instance => $asset_spec } );
+        }
+    }
     my $key   = shift;
     my $score = $scores->{$key};
     $session->log->debug("[$key] resolves to [$score]");
-    return $score; # scalar variable, so no need to clone
+    return $score;    # scalar variable, so no need to clone
 }
 
 =head2 jump
@@ -71,17 +110,18 @@ catch the first successful jump.
 sub jump(&$) {
     my ( $sub, $target ) = @_;
     $jump_count++;
-    
+
     # If $validTargets known, make sure target is valid
-    if ($validTargets && !exists $validTargets->{$target}) {
+    if ( $validTargets && !exists $validTargets->{$target} ) {
         $session->log->debug("Invalid target [$target]");
         if ($validate) {
-            die("Invalid jump target \"$target\""); # bail and report error
-        } else {
-            return; # skip jump but continue with expression
+            die("Invalid jump target \"$target\"");    # bail and report error
+        }
+        else {
+            return;                                    # skip jump but continue with expression
         }
     }
-        
+
     if ( $sub->() ) {
         $session->log->debug("jump call #$jump_count is truthy");
         die( { jump => $target } );
@@ -120,8 +160,12 @@ A gotoExpression is essentially a perl expression that gets evaluated in a Safe
 
 To access Section/Question recorded response values, the expression calls L<value>.
 To access Section/Question recorded response scores, the expression calls L<score>.
+Both L<value> and L<score> allow you to resolve values and scores from other completed survey
+instances.
+
 To trigger a jump, the expression calls L<jump>. The first truthy jump succeeds.
-We also give expressions access to some useful utility subs such as avg(), and all of the 
+
+Expressions also have access to some useful utility subs such as avg(), and all of the 
 handy subs from List::Util (min, max, sum, etc..).
 
 A very simple expression that checks if the response to s1q1 is 0 might look like:
@@ -131,7 +175,7 @@ A very simple expression that checks if the response to s1q1 is 0 might look lik
 A more complicated gotoExpression with two possible jumps might look like:
 
  jump { value(q1) > 5 and value(s2q1) =~ m/textmatch/ } target1;
- jump { avg(value(q1), value(q2), value(q3)) > 10 } target2;
+ jump { avg(value(q1), value(q2), value(home/anotherSurvey, q3)) > 10 } target2;
 
 =head3 opts (optional)
 
@@ -166,52 +210,113 @@ sub run {
         = validate_pos( @_, { isa => 'WebGUI::Session' }, { type => SCALAR }, { type => HASHREF, default => {} } );
 
     # Init package globals
-    ( $session, $values, $scores, $jump_count, $validate, $validTargets ) = ( $s, $opts->{values}, $opts->{scores}, 0, $opts->{validate}, $opts->{validTargets} );
-    
-    if (!$session->config->get('enableSurveyExpressionEngine')) {
+    ( $session, $values, $scores, $jump_count, $validate, $validTargets )
+        = ( $s, $opts->{values}, $opts->{scores}, 0, $opts->{validate}, $opts->{validTargets} );
+
+    if ( !$session->config->get('enableSurveyExpressionEngine') ) {
         $session->log->debug('enableSurveyExpressionEngine config option disabled, skipping');
         return;
     }
 
-    # Create the Safe compartment
-    my $compartment = Safe->new();
+    REVAL: {
 
-    # Share our utility subs with the compartment
-    $compartment->share('&value');
-    $compartment->share('&score');
-    $compartment->share('&jump');
-    $compartment->share('&avg');
-    
-    # Give them all of List::Util too
-    $compartment->share_from('List::Util', ['&first', '&max', '&maxstr', '&min', '&minstr', '&reduce', '&shuffle', '&sum',]);
+        # Create the Safe compartment
+        my $compartment = Safe->new();
 
-    $session->log->debug("Expression is: \"$expression\"");
-    $compartment->reval($expression);
-    
-    # See if we ran the engine just to check for errors
-    if ($opts->{validate}) {
-        if ($@ && ref $@ ne 'HASH') {
-            my $error = $@;
-            $error =~ s/(.*?) at .*/$1/s; # don't reveal too much
-            return $error;
+        # Share our utility subs with the compartment
+        $compartment->share('&value');
+        $compartment->share('&score');
+        $compartment->share('&jump');
+        $compartment->share('&avg');
+
+        # Give them all of List::Util too
+        $compartment->share_from( 'List::Util',
+            [ '&first', '&max', '&maxstr', '&min', '&minstr', '&reduce', '&shuffle', '&sum', ] );
+
+        $session->log->debug("Expression is: \"$expression\"");
+
+        $compartment->reval($expression);
+
+        # See if we ran the engine just to check for errors
+        if ( $opts->{validate} ) {
+            if ( $@ && ref $@ ne 'HASH' ) {
+                my $error = $@;
+                $error =~ s/(.*?) at .*/$1/s;    # don't reveal too much
+                return $error;
+            }
+            return;                              # no validation errors
         }
-        return; # no validation errors
-    }
 
-    # A successful jump triggers a hashref containing the jump target to be thrown
-    if ( ref $@ && ref $@ eq 'HASH' && $@->{jump} ) {
-        my $jump = $@->{jump};
-        $session->log->debug("Returning [$jump]");
-        return $jump;
-    }
+        # A successful jump triggers a hashref containing the jump target to be thrown
+        if ( ref $@ && ref $@ eq 'HASH' && $@->{jump} ) {
+            my $jump = $@->{jump};
+            $session->log->debug("Returning [$jump]");
+            return $jump;
+        }
 
-    # Log all other errors (for example compile errors from bad expressions)
-    if ($@) {
-        $session->log->error($@);
-    }
+        # See if an unresolved external reference was encountered
+        if ( ref $@ && ref $@ eq 'HASH' && $@->{other_instance} ) {
+            my $asset_spec = $@->{other_instance};
+            $session->log->debug("Resolving external reference: $asset_spec");
+            my $asset;
 
-    # Return undef on failure
-    return;
+            # Instantiate the asset to check it is a Survey instance, and to grab its assetId
+            if ( $session->id->valid($asset_spec) ) {
+                $asset = WebGUI::Asset->new( $session, $asset_spec );
+            }
+            if ( !$asset ) {
+                $asset = WebGUI::Asset->newByUrl( $session, $asset_spec );
+            }
+            if ( ref $asset ne 'WebGUI::Asset::Wobject::Survey' ) {
+                $session->log->warn("Not a survey instance: $asset_spec");
+                return;
+            }
+            if ( !$asset ) {
+                $session->log->warn("Unable to find asset: $asset_spec");
+                return;
+            }
+            my $assetId = $asset->getId;
+
+            # Get the responseId of the most recently completed survey response for the user
+            my $userId = $opts->{userId} || $session->user->userId;
+            my $mostRecentlyCompletedResponseId = $session->db->quickScalar(
+                "select Survey_responseId from Survey_response where userId = ? and assetId = ? and isComplete = 1",
+                [ $userId, $assetId ]
+            );
+
+            if ( !$mostRecentlyCompletedResponseId ) {
+                $session->log->debug("User $userId has not completed Survey");
+                return;
+            }
+            $session->log->debug("Using responseId: $mostRecentlyCompletedResponseId");
+
+            # (re)Instantiate the survey instance using the responseId
+            use WebGUI::Asset::Wobject::Survey;
+            $asset = WebGUI::Asset::Wobject::Survey->newByResponseId( $session, $mostRecentlyCompletedResponseId );
+            $asset->responseIdCookies(0);
+            if ( !$asset ) {
+                $session->log->warn("Unable to instantiate asset by responseId: $mostRecentlyCompletedResponseId");
+                return;
+            }
+
+            $other_instances->{$asset_spec} = {
+                values =>
+                    $asset->responseJSON( undef, $mostRecentlyCompletedResponseId )->responseValuesByVariableName,
+                scores =>
+                    $asset->responseJSON( undef, $mostRecentlyCompletedResponseId )->responseScoresByVariableName,
+            };
+            $session->log->debug("Successfully looked up asset: $assetId. Repeating reval.");
+            redo REVAL;
+        }
+
+        # Log all other errors (for example compile errors from bad expressions)
+        if ($@) {
+            $session->log->error($@);
+        }
+
+        # Return undef on failure
+        return;
+    }
 }
 
 1;
diff --git a/t/Asset/Wobject/Survey/ExpressionEngine.t b/t/Asset/Wobject/Survey/ExpressionEngine.t
index e0fb49817..a47ad2bbe 100644
--- a/t/Asset/Wobject/Survey/ExpressionEngine.t
+++ b/t/Asset/Wobject/Survey/ExpressionEngine.t
@@ -22,23 +22,24 @@ my $session = WebGUI::Test->session;
 
 #----------------------------------------------------------------------------
 # Tests
-my $tests = 36;
+my $tests = 41;
 plan tests => $tests + 1;
 
 #----------------------------------------------------------------------------
 # put your tests here
 
 my $usedOk = use_ok('WebGUI::Asset::Wobject::Survey::ExpressionEngine');
-
+my ($user, $survey);
 SKIP: {
 
     skip $tests, "Unable to load ExpressionEngine" unless $usedOk;
 
     my $e = "WebGUI::Asset::Wobject::Survey::ExpressionEngine";
 
+    WebGUI::Test->originalConfig('enableSurveyExpressionEngine');
+    $session->config->set( 'enableSurveyExpressionEngine', 0 );
     is( $e->run( $session, 'jump { 1 } target' ),
         undef, "Nothing happens unless we turn on enableSurveyExpressionEngine in config" );
-    WebGUI::Test->originalConfig('enableSurveyExpressionEngine');
     $session->config->set( 'enableSurveyExpressionEngine', 1 );
     is( $e->run( $session, 'jump { 1 } target' ), 'target', "..now we're in business!" );
 
@@ -109,8 +110,61 @@ SKIP: {
         undef, 'target is not valid' );
     is( $e->run( $session, q{jump {1} target}, { values => \%values, validTargets => { target => 1 } } ),
         'target', '..whereas now it is ok' );
+    
+    
+    # Create a test user
+    my $user = WebGUI::User->new( $session, 'new' );
+    
+    # Create a Survey
+    my $survey = WebGUI::Asset->getImportNode($session)->addChild(
+        {   className                => 'WebGUI::Asset::Wobject::Survey',
+        },
+    );
+    isa_ok($survey, 'WebGUI::Asset::Wobject::Survey');
+    my $url = $survey->get('url');
+    my $id = $survey->getId;
+    
+    $survey->surveyJSON->newObject([]); # s0
+    $survey->surveyJSON->newObject([0]); # s0q0
+    $survey->surveyJSON->newObject([0,0]); # s0q0a0
+    $survey->surveyJSON->newObject([0]); # s0q1
+    $survey->surveyJSON->newObject([0,1]); # s0q1a0
+    
+    $survey->surveyJSON->section([0])->{variable} = 'ext_s0';
+    $survey->surveyJSON->question([0,0])->{variable} = 'ext_s0q0';
+    $survey->surveyJSON->question([0,1])->{variable} = 'ext_s0q1';
+    $survey->surveyJSON->answer([0,0,0])->{recordedAnswer} = 'ext_s0q0a0';
+    $survey->surveyJSON->answer([0,0,0])->{value} = 150; # worth 150 points
+    $survey->surveyJSON->answer([0,1,0])->{recordedAnswer} = 'ext_s0q1a0';
+    $survey->surveyJSON->answer([0,1,0])->{value} = 50; # worth 50 points
+    
+    $survey->responseIdCookies(0);    # disable cookies so that test code doesn't die
+    my $responseId = $survey->responseId($user->userId);
+    
+    my $rJSON = $survey->responseJSON(undef, $responseId);
+    $rJSON->recordResponses({
+        '0-0-0'        => 'My ext_s0q0a0 answer',
+        '0-1-0'        => 'My ext_s0q1a0 answer',
+    });
+    
+    # Remember to persist our changes..
+    $survey->persistSurveyJSON();
+    $survey->persistResponseJSON();
+    $survey->surveyEnd;
+    
+    is( $e->run( $session, qq{jump {value('$id', ext_s0q0) eq 'ext_s0q0a0'} target}, {userId => $user->userId} ),
+        'target', 'external value resolves ok when id used' );
+    is( $e->run( $session, qq{jump {value('$url', ext_s0q0) eq 'ext_s0q0a0'} target}, {userId => $user->userId} ),
+        'target', 'external value resolves ok when url used' );
+    is( $e->run( $session, qq{jump {score('$url', ext_s0q0) == 150} target}, {userId => $user->userId} ),
+        'target', 'external score resolves ok too' );
+    is( $e->run( $session, qq{jump {score('$url', ext_s0) == 200} target}, {userId => $user->userId} ),
+        'target', 'external score section totals work too' );
 }
 
 #----------------------------------------------------------------------------
 # Cleanup
-END { }
+END { 
+    $user->delete if $user;
+    $survey->purge if $survey;
+}