public IQueryable<IGrouping<ResponseHeader, Response>> LoadResponses(int surveyId)
{
var responses = from response in this.Context.Responses
where response.SurveyId == surveyId
&& response.UserResponse != null
orderby response.QuestionRelativeOrder
select response;
return from response in responses
group response by response.ResponseHeader into responsesByHeader
orderby responsesByHeader.Key.CreationDate descending
select responsesByHeader;
}