There are more questions than answers following NBA commissioner David Stern’s press conference Tuesday about the Tim Donaghy officiating scandal. A pile of good ones have come our way here in the Covers.com newsroom and we’ve been poring over our exclusive referee statistics in search of clues.

Here are some of the key questions and the answers based on our research so far.

Is it possible to tell with certainty whether Donaghy was involved in fixing games based on the numbers alone?

Short answer: no. There are some intriguing trends that raise some questions but they don’t come close to proving anything on their own. I noted some of them in my column on Tuesday. The truth is there are a lot of officials who have disproportional trends in their stats but it doesn’t mean they’ve done anything wrong according to NBA rules.

Have you found any other numbers worth noting since Tuesday?

Yes. But again they don’t prove anything standing on their own. If you’re interested, here’s what we found: 

- In each of the past two seasons, Donaghy has been among the top six NBA officials with the most disproportional average points per game compared to the average over/under line in his games. In 2006-07, the games in which he officiated saw an average of 201.2 points per game compared to an average over/under of 196.26 in those games – a difference of 4.94 points. That ranks as the fourth-most disproportional in the NBA. The year before, he had a difference of 4.66 points which ranked sixth. To see more, click on this chart.

- The average differential for all referees for the 2006-07 season was 2.07 points.

- Here is the over-to-under record for Donaghy’s games over the past four seasons in games in which his crew called more than 50 fouls: 2006-07: 13-4-1; 2005-06: 27-7; 2004-05: 12-11-1; 2003-04: 10-9; 2002-03: 10-5-1; 2001-02: 5-2

- Since the 2004-05 season, Donaghy has gone from averaging 193.72 points per game in the games his crews officiated to 201.2 points in the 2006-07 season. Has he had significant jumps like this before? Yes. He averaged 193.55 points in the 2002-03 season and then averaged more than seven points fewer in 2003-04 with 184.14.

Have other officials had jumps in points per game from one season to another similar to Donaghy's?

It happens all the time. Tony Nunez Jr. is one of many examples. Just last year he made an incredible jump of 11.7 points from the season before. In 2006-2007, his crews averaged 202.4 points per game compared to 190.7 points from the 2005-06 season. This is part of a general pattern of inconsistency with NBA officiating.  

In your opinion, would it be easier to try to fix pointspreads or over/unders?

I’d say over/unders (or totals) would be easier to try to fix on the floor. You would do that by calling fouls in certain situations and you could do it without showing as much bias as you would if you were trying to get one team to cover the spread against another.

Here’s the catch and it's a big one: You would make far less money betting on totals than you would betting on spreads, which longtime oddsmaker Keith Glantz reminded me of yesterday. Almost all books – legal or illegal – have significantly lower limits on over/under bets than they do on pointspreads for the very reason that totals are easier to fix. So if we’re talking about a really greedy group of people here, rigging pointspreads would be far more enticing than rigging totals.

Should the NBA have picked up on this sooner?

Based on the numbers, there’s nothing