Rendering different view classes based on the value of a string
The obvious answer is to introduce a map:

var typeToConstructor = {
    'face' : FaceDetail,
    'voice' : VoiceDetail,
    // ...
}


Then you can simply look up your constructor function:

onShow: function() {
    var type = this.model.get('type').toLowerCase();
    var constructor = typeToConstructor[type];
    if (typeof constructor !== 'function') {
        // Unknown type... do something
    }

    // execute the constructor.
    this.regionItems.show(new constructor({
        model               : this.model,
        authRequestModel    : this.authRequestModel,
        collection          : this.model.attemptItemsDataCollection
    });
}