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Third in a four-part NFL draft data series.

Winning a Super Bowl is the ultimate goal. When 32 teams turn their focus to Chicago in two weeks, prepared to make their selections in the upcoming NFL draft, they have one purpose in mind.

With the annual glitz and hype, each draft feels like the biggest event on the NFL’s offseason calendar. Draft picks are instantly analyzed. Before the sun rises, each team is labeled a winner or loser.

It’s easy to get lost in hysteria. The question is how much does success in the draft actually correlate to winning? Searching for an answer, USA TODAY NETWORK-Wisconsin conducted an extensive study to gauge how strongly certain aspects of draft management can be linked to success on the field.

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The study uncovered two significant correlations: teams with fewer rookie snaps and more retention of their draft picks tend to win more games.

The first step is to establish what qualifies as success in the NFL. Winning percentage is vital, but measuring teams exclusively on their win-loss record can be misleading. The Green Bay Packers had one of the best regular seasons in NFL history with a 15-1 record in 2011, but the ending ultimately wasn’t as satisfying as their 2010 season, when they were 10-6. Why? Because winning a Super Bowl is the ultimate goal.

To consider the regular season’s importance without neglecting the gravity of a postseason run, USA TODAY NETWORK-Wisconsin created a formula that calculates a team’s “weighted wins” total. Our formula is simple. Each regular-season victory since 2005 is worth one win. For each round of the playoffs, teams are rewarded an extra quarter of a win.

Here’s a key to show how each win is weighted:

» Regular-season victory = 1 win.

» Wild-card victory = 1.25 wins.

» Divisional-round victory = 1.5 wins.

» Conference championship game victory = 1.75 wins.

» Super Bowl victory = 2 wins.

A team’s postseason weighted wins total compounds as it advances through the playoffs. So a Super Bowl victory is worth two wins, but that’s added to the value already accumulated through the playoffs for a total of six weighted wins. A team that advances to the conference championship game earns 1.25 weighted wins for clearing the wild-card round and 1.5 wins for winning the divisional, earning 2.75 extra postseason weighted wins.

The formula provides significant credit for playoff success, without ignoring the regular season’s importance. In 2011, the Packers received 16.25 weighted wins: 15 for the regular season, 1.25 for their first-round bye. Their 2010 team that finished 10-6 but won Super Bowl XLV received 16 weighted wins: 10 in the regular season, six in the postseason.

The formula isn’t perfect. Overall, it passes the logic test. Since 2005, the New England Patriots have dominated every other team with an NFL-leading 163 weighted wins. Rounding out the top five are the Pittsburgh Steelers (129.75), Indianapolis Colts (127.5), Denver Broncos (124.5) and Packers (123.75).

The league’s bottom five since 2005: Tampa Bay Buccaneers (67), Detroit Lions (62), Cleveland Browns (57), Los Angeles Rams (56) and Oakland Raiders (54).

Using the Spearman Rank-Order Correlation, which finds the relation between two rankings, the next step is to find what set of data correlates closest with the 32-team weighted wins ranking. After plugging the numbers into a simple equation — and sparing you the algebra — the output is a number between one and negative one. The closer that number is to one, the stronger its positive correlation.

Before correlating the draft, let’s start with something everyone knows impacts success on the field. The great myth about football is that it’s the “ultimate team game” in sports. In reality, the quarterback position is so vital, it isn’t merely the most important position in the game. No, quarterback is almost always the lone prerequisite for Super Bowl contention.

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It isn’t a perfect stat, but the best single-number indicator of quarterback play is a team’s average passer rating. Since 2005, average passer rating has a .81 correlation with weighted wins, a connection so strong it suggests causation. An NFL team is successful because it has a franchise quarterback. This is a surprise to no one.

There is nothing in the draft that correlates to NFL success as closely as quarterback play. Its necessity is why the Los Angeles Rams were willing to forfeit large chunks of their next two drafts for this year’s No. 1 overall selection, providing the chance to draft the quarterback of their choice.

Whichever quarterback the Rams draft, they will be under immense pressure to play him as early as possible. They would be wise to delay that choice as long as possible.

Among 31 categories, the strongest correlation between draft management and NFL success is a team’s ability to limit rookie playing time. On average, fewer rookie snaps has a .66 correlation to NFL success. For comparison, average scoring defense since 2005 has an identical .66 correlation.

Another way to gauge how much teams limit rookie participation is the number of first-year players that are on the field for 400 snaps. The 400-snap mark is an arbitrary minimum to qualify as a part-time player. Since 2005, teams with fewer 400-snap rookies have a .60 correlation with success in the NFL.

So a high number of rookie snaps is clearly a negative, not a positive. Theoretically, that negative would coincide with a positive. Maybe the strongest positive relating to NFL success is retention of draft picks.

Teams that keep a higher percentage of their draft picks four full seasons — through the end of their rookie contract — have a .44 correlation with NFL success. That number increases to .56 correlation if the Patriots are removed. Why remove the Patriots? Bill Belichick’s team is an extreme outlier. The league’s most successful franchise over the past decade ranks 30th with 29.7 percent of its draft picks retained four full seasons. (Keep in mind, the last four-year rookie cycle doesn’t extend past the 2012 draft.)

It’s interesting to see what happens when NFL success is compared to composite rankings of average rookie snaps and retention. The outcome is a .61 correlation, even stronger than average scoring defense since 2005.

The Packers rank 10th in the composite rankings: 13th in the NFL with 218.32 average rookie snaps per total drafted, ninth with 43.2 percent of their drafted players retained four full seasons.

While two draft management categories don’t provide enough sample size to rank teams based on their drafting, it suggests general manager Ted Thompson has done an adequate job following a successful model of patiently allowing his drafted players to develop.

Thompson has faced plenty of criticism for his inability — or unwillingness — to dabble in free agency. Yes, there are times a free-agent signing makes sense for a team on the doorstep of a championship. But if two-time MVP quarterback Aaron Rodgers is the biggest reason for the Packers’ contention, Thompson has made things easier with his draft-and-develop tendencies.

rwood@gannett.com and follow him on Twitter @ByRyanWood

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