@sgrif 

The nice thing about @jdkanani 's code is that we can reuse that function across multiple relations in a `AssociatedModel`. More importantly, even across different `AssociatedModel` types. Passing in relation helps in this scenario. See the snippet below

```javascript

function simplePolymorphicRelation(attributes, relation) {
     var key = relation.key; // shows use of relation
     return Models[attributes[key+ '_type'] || this.get(key+ '_type')];
};

Models.Job = Backbone.AssociatedModel.extend({
  relations: [
    {
      type: Backbone.One,
      key: 'organizable',
      relatedModel: simplePolymorphicRelation
    }
  ]
});

Models.Article = Backbone.AssociatedModel.extend({
  relations: [
    {
      type: Backbone.One,
      key: 'organizable',
      relatedModel: simplePolymorphicRelation
    }
  ]
});

```