two way binding in angularjs transcluded content

Why doesn't the two way binding work in the following directive?

Module:

angular.module('main')
.controller('MainController', ['$scope', 'TestService', function ($scope, TestService) {
    $scope.name = "Aaron";

    $scope.data = "Initial";

    $scope.dataClicked = function () {
        alert($scope.data);
    };
}]);

Directive:

var angularStartDirectives = angular.module('angularStart.directives', []);    
angularStartDirectives.directive('outputText', function () {
    return {
        transclude: true,
        template: '<div ng-transclude></div>'
    };
});

Form:

<form>
    <div data-output-text>
        <p>Hello {{name}}</p>
        <input type="text" ng-model="data" />
    </div>
    <div>{{data}}</div>
    <button type="button" ng-click="dataClicked()">Go</button>
</form>

The result is that the transcluded content receives the value of $scope.data initially but updates to the bound input do not propagate up to the parent scope.