I started this series last week and it seemed to be received well and with interest. If you missed the first post, you can read it here. To sum it up, what I am attempting to do is to rank how well teams have executed throughout all of their games this season. To accomplish this, I have written a simple algorithm that compiles several statistics and returns a number for each team. Then I rank these values in order from highest to lowest. While you can read a lot more about exactly what the numbers mean in the link up there, there were a few things I wanted to clear up in response to the comments from the first post.

• The values assigned to each team are, by definition, index values. This means they have absolutely no meaning unless they are compared to each other. A team with a negative value is not necessarily "bad" unless the other teams have positive values. Even though this ends up being the case in my model, it is still something to keep in mind.
• I saw some comparisons to Pro Football Focus and Cold Hard Football Facts. I do not intend for my system to be "better" than someone else's, nor do I think that I am an "expert" at this. If you prefer how they do things, that's fine. This is literally something I am doing in my spare time for fun.
• Speaking of spare time, that is something I have very little of. I really liked the suggestion of running my algorithm against previous years to see how it fared, and if I ever get an afternoon to work this over, I will post the results.
• These rankings should not be used to determine the outcome of individual games. Games are too erratic to be predicted by pure numbers; this is why computer simulations run thousands of games to determine a winner. Additionally, these numbers will not separate "good" teams from "bad" ones. Those words are subjective. Numbers are not. All this does is compile statistics using simple arithmetic. There is no consideration of how "good" a team is when my spreadsheet does the math. Like I mentioned above, the values rate how well a team executes, not how good they are perceived to be.

Before unveiling the rankings for this week, I would like to offer an apology. While working through the numbers this week, I noticed a small error I had made that had large consequences. It only affected the ranking of the Bengals, but because I had misplaced a negative sign, it had essentially given them twenty free points. While this doesn't really change the Eagles' ranking or number, it does affect the integrity of these posts. I was pressed for time last week, was rushed to post the rankings before the Thursday night football game, and skipped the check that I normally do to catch errors like that. I will never make that mistake again, even if I miss posting the numbers for Thursday night. I'm very embarrassed that it happened and would very much appreciate it if we keep the comments to be about this week's rankings instead of how I messed up.

With all of that being said, I'll move on to the rankings, which I did double-check this week. There is a new column in the chart that shows how each team has moved up or down the rankings in comparison to last week. A "0" indicates that they did not move at all.

I spent this space last time explaining my system more intricately. Since I really don't have to do that again, I thought I'd start with some overall things that I noticed while compiling the statistics and finish off with a comparison with the Eagles' numbers versus their upcoming opponent. If there's anything else you think I should be discussing here, let me know in the comments. Onto some thoughts:

• Statistic of the week. Since a lot of people were interested in the inner workings of the model, I figured I talk about one component of it during these posts. One of my favorite numbers to look at is the defensive line (which technically includes linebackers, but I group it in the line for convenience). The statistic is simply the yards per carry allowed subtracted from the sacks forced per game. Of all the teams, Miami is the only one who is positive in this category (3 sacks per game to 2.7 yards per carry).
• The 49ers may have a loss, but winning your last two games by a combined score of 79-3 should be enough to get to the top pretty much everywhere.
• Getting Rashard Mendenhall and James Harrison back seemed to really help the Steelers' cause last week as they jumped up seven spots to crack the top ten. The same could not be said for Atlanta, who despite remaining undefeated drop down three places to fifth after another close game.
• New England has a notoriously terrible defense, but it might not matter much since they are already +10 on the turnover ratio through five games this season. It's still a long way to meet the standard set by San Francisco last year, who finished an incredible +26.

Let's take a look at Lions-Eagles. Even though Detroit is in a similar position to the Steelers - they have their backs against the wall and are coming off their bye week - this match-up really could be a good one for Philadelphia. I am right now in the school of thought that the offense just needs a boost of confidence to at least start being competent, and it hasn't helped that they've played some decent defenses pretty much the entire season.

The Lions, however, have not been a good defense this season. In spite of having nice "bulk" numbers (rushing yards allowed, passing yards allowed, etc.), they have given up about four touchdowns per game. More importantly, they are terrible at forcing turnovers. As in, "they haven't even recorded an interception" terrible. If you buy that Vick tried to protect the ball last Sunday (which I think is true for the only fumble that ultimately mattered) then they shouldn't have any trouble keeping the ball on Sunday. Overall, the Lions are only recovering 0.8 fumbles per game and opposing quarterbacks have an interception percentage per pass attempt of 0.00%.

On offense, Detroit has almost no respectable ground game and are giving up 2.2 sacks per game. If there is any game for the pass rush to get going, it is this one, especially since Calvin Johnson is so good you couldn't cover him with a blanket. On the other hand, their defensive line is also forcing 2.2 sacks per game but is giving up over four yards per carry, suggesting that a healthy does of LeSean McCoy may pay out nicely for the Eagles. Whether Andy does this or not remains to be seen.

It will be interesting to see how the defense holds up overall. The defensive line hasn't posted any impressive tangible statistics, but the performance by the secondary (allowing only 5.7 yards per attempt and an interception percentage of 3.33%) almost makes this an afterthought. The defensive performance is somewhat a reversal of how they played last year - holding teams to fewer points with great coverage but with fewer sacks. The defense has truly carried this team, which isn't a bad thing (I bet any coach would tell you they'd rather be carried by their defense than their offense). Hopefully they can keep up the solid play against a potent, albeit one-dimensional, Lions offense.

Ultimately, this seems to me like it will be the most important game of the season so far. The Lions' defense is horrible at the two things hampering the Eagles' offense - turnovers and scoring - so we will get a chance to see if the offensive futility is an internal or circumstantial issue. Additionally, the Eagles are fully healthy (as Jason mentioned earlier) and are playing at home. I'll say this right now: if they don't score at least twenty-one points this week, the Eagles may be in for a long season. All the statistics right now are in the Eagles favor, giving them a golden opportunity to gain some momentum heading into their bye. If they don't live up to the potential this game, it's possible that what we've seen through five games out of the offense is what we'll get the rest of the year.