Well, let's start from the start, you get 3pts for a win, 1pt for a draw and 0pts for a loss, you also get points based on how many of your opponents nominated you as their favourite opponent of the weekend. GW's method for ranking you in the tournament is (as best as I can tell) the following; the average score across all the players who used the same codex is compared with your tournament score and the difference is you "ranking score". For example I scored 12pts for my 4 wins and 1 point because someone thought I was a good opponent. The average score across the 7 Ork Players at the tournament was 11 so that gives me a ranking score of 2. Mick scored 13 points as well but the average score across the 11 Space Wolf players was 8 so his ranking score was 5.
Using the above methodology Mick placed 6th and I placed 44th out of a field of 129 players. It's GW's tournament and they can score it how they like (also I knew this would be the case going into the event so I'm not complaining), I'm just not sure what that system tells us in the final standings. Except, possibly that if you do well with an army that other players did not manage to do well with then you are likely to do well in the overall standings.
Where this gets iffy is when someone with a 4-1 record wins the tournament with Daemons while the only player with 5 wins finishes 8th, so you're not really in control of your final placing.
Let's just take a look at where we would have finished if the rankings were based on your results with the codex ranking score used as a tie-breaker. In this case Mick would have placed 11th and I would have got 19th. The 5-0 Dark Eldar player still only manages second place though because an Ork player with 4 wins managed 5 best game nominations and so ended up with 17 total points to beat him by a single point. So it comes back to the age old issue of soft scoring vs generalship but all I can say to that is that if you know how the scoring is done before you go to the event and buy the ticket anyway don't complain about the rubric after the fact.
What I take away from this tournament is that I played well and managed 4 wins, I had 5 great games against 5 really nice opponents and I would definitely buy a ticket for another Throne of Skulls.
Just in case you're interested, here's how the codexes break down in terms of number of players and average score:
|No. of players||Codex||Avg Score|
|8||Chaos Space Marines||8.38|