ungraded is not correct

Tim-I've been having a problem since the essay beta version. I had hoped it would go away with the upgrade to 1.6, but it hasn't. The problem is that even after I grade essay questions, some are still being included in the totals of ungraded questions. In order to be able to give you some useful information from my database to troubleshoot this, I need to understand what the following line from mod/quiz/grading/report/grading/report.php does:

// determine the number of ungraded attempts

$ungraded = 0;

foreach ($attempts as $attempt) {

if (!$this->is_graded($question, $attempt))

{ $ungraded++; }

}

What I need to know is what fields in the database is it looking at to determine whether a question has been graded or not. If I know that, I can see what information is in those fields to troubleshoot this.

In the past, I have manually fiddled with the database by trial and error (unfortunately, something I have to do a lot with the quiz module) to get it working, but it hasn't been systematic. So if you can tell me how this number is calculated I can make a more systematic attempt at finding out the source of the problem.