anchor.diff:  
       foreach my $test_desc ( keys %$href )
       {
  -        foreach my $metric ( keys $href->{$test_desc} )
  +        foreach my $metric ( keys %{ $href->{$test_desc} })
           {
               my $sense = get_column_sense( $metric );
   
               if( $sense =~ /smaller is better/ )
               {
  -                foreach my $device_id ( keys $href->{$test_desc}{$metric} )
  +                foreach my $device_id ( keys % { $href->{$test_desc}{$metric} })
                   {
                       negate( $href->{$test_desc}{$metric}{$device_id} );
                   }
  
positive.code: 
      foreach my $test_desc ( keys %std_scores )
      {
          foreach my $metric ( keys $std_scores{$test_desc} )
          {
              my @values = values $std_scores{$test_desc}{$metric};
       
              my $min = min( @values );
              my $max = max( @values );
              
              foreach my $device_id ( keys $std_scores{$test_desc}{$metric} )
              {
                  my $value = $std_scores{$test_desc}{$metric}{$device_id}; 
  
  
negative.code: 
      foreach my $test_desc ( keys %normalized_scores )
      {
          foreach my $metric ( keys %{$normalized_scores{$test_desc} })
          {
              foreach my $device_id (
                  keys %{ $normalized_scores{$test_desc}{$metric} })
              {
                  my @row_data = (
                      $device_id_to_display_name{$device_id},
  