The Pittsburgh Penguins fired general manager Ray Shero this past week following a Game 7 loss to the New York Rangers. Evaluating the merits of an executive is tough, because so much of it can be process versus results, and it's tough to know exactly what parts of the process are due to the manager alone.

We can, however, look at the results to get a better picture of what happened under Shero, and look ahead to what the next GM has to work with.

Shero’s draft and development results

One main issue brought up during the Ray Shero era was that he wasn't able to acquire forward talent through the draft to provide depth behind the superstars. There's merit to that claim. In general, there is a positive correlation between games played and player ability. In general, that makes sense. If a player is capable of contributing at the NHL level, the GM will want him on the roster and the coach will want him on the ice. There's a caveat, however, which we'll get to in a little bit. First, let's see how the Pens ended up with so few talented forwards in their system.

Out of 16 total forward picks by the Penguins between 2007-11 (including three in the No. 20-to-60 range), the Penguins have had just one play more than 100 games in the NHL -– Dustin Jeffrey (since traded to the Stars). The highest-drafted forwards, Angelo Esposito (No. 20, 2007), Keven Veilleux (No. 51, 2007) and Beau Bennett (No. 20, 2010), have combined for a total of 47 NHL games played, all by Bennett.

Bennett could still end up being a long-term quality player, although his health has been an issue in his early career (he played in 21 games in 2013-14, and is set to undergo surgery this offseason). Overall, however, Pittsburgh hasn't seen much quality performance from any recently drafted forwards who are still on the roster.

Now for that caveat: opportunity. Games played isn’t a perfect lens through which to view draft success because it doesn’t account for games missed due to injury (as we’ve seen with Bennett) or lack of opportunity. The Penguins have been a very good team since 2007-08 and have relied heavily on veterans to fill their secondary scoring roles behind Sidney Crosby and Evgeni Malkin. There was seldom a need for a young forward to be pressed into action when the Pens’ roster boasted names like Marian Hossa, Jarome Iginla or James Neal, the last of whom was purchased with prospects and draft picks.

But it also begs the question if any of the Penguins’ forward prospects were knocking on the door? Based on who they’ve selected -- and with few forwards among their top prospects as recently as September 2013 -- it certainly seems like the Penguins have needed to go outside their system to find secondary scoring help because an internal option didn’t exist. And that hasn’t been the case with a few of Pittsburgh’s comparably successful peers.

Perennially contending clubs like the Chicago Blackhawks and San Jose Sharks have managed to infuse some of their forward picks from those drafts. Brandon Saad (No. 43 in 2011) and Charlie Coyle (No. 28, 2010, since traded to Minnesota in the Brent Burns package) are among the valuable forwards taken by the two clubs in those drafts.

But while Shero could be criticized for failing to draft an impact prospect at forward, he hasn't been drafting busts. Rather, the Penguins have been acquiring a high volume of defensemen with early picks. Since 2009, the Penguins have spent six of nine total first- and second-round picks on defensemen. That’s part of the explanation as to why there's a lack of quality young forward prospects behind the stars, with the decent-but-not-great Oskar Sundqvist the gem of the system right now. Those defensemen have been the strength of the Penguins' system, which was evident when rookie Olli Maatta helped carry the Pens in 2013-14 as the roster was beset by injuries. Shero wasn’t wasting picks; it’s just been a tradeoff. In some cases, literally. The Penguins have dealt some of their defensive depth to land veteran forwards (e.g., Joe Morrow for Brenden Morrow at the 2013 deadline).

You can’t just focus on the forwards if you’re going to evaluate Shero’s draft record. And you also have to account for another key factor.

The role of luck in drafting

About half of the teams who picked at least one forward between the 20th and 60th pick between 2007-11 actually got a solid NHL forward who has contributed extensively in the league. So immediately we’re looking at a coin flip regardless of who is making the pick. But even if you put the blame for drafting entirely on Shero -- which is a giant assumption, given that he had a staff of scouts and assistants -- you have to consider the role luck plays in the draft.

Neil Paine at ESPN affiliate fivethirtyeight.com explored this concept for the NFL draft with a principle described as the "paradox of skill," meaning that most NFL evaluators are so close in talent that the only differences in draft results come from luck.

This may exist in the NHL, too. I mimicked Neil's methods for the 2006 through 2010 NHL drafts (giving the players time to develop). "Value" is defined as relative to the average output for each draft slot; put another way, did a team get better or worse value from all their draft slots compared to an average team? If skill outweighs luck when it comes to the draft, you’d expect to see a lot of marks in the upper right quadrant (consistently good) or lower left quadrant (consistently bad). Instead, this is what we see:

The sample is 15 years smaller than Neil's, but the results are mostly the same. In that five-year span, there was no correlation between drafting skill in subsequent seasons.

Part of this could be due to the “paradox of skill” among NHL scouts, or it could be that it takes a lengthy amount of time for evaluators to differentiate themselves. Regardless of the sample size used, there is nothing from this time span that indicates the Pens' poor drafting was anything other than poor luck. And if one or two picks go a better way for Pittsburgh (and again, consider Bennett’s injuries after recording 14 points in 26 games in 2013), there wouldn't be as much uproar over Shero's draft record.

Using solely draft results as a major reason for a front-office shakeup would be a mistake: Shero is leaving his successor with a strong group of young defensemen, players who can potentially be dealt elsewhere to shore up other areas, as he did himself in the past. Should he be held accountable there?

Too many draft-pick trades?

What a manager can affect pretty directly is the assets he controls and moves in trades. Shero moved a number of high picks during his tenure, in attempts to strengthen his club for Stanley Cup runs. Putting aside players like Esposito, Morrow and Carl Sneep -- whom the Penguins drafted then traded, but have not made an impact at the NHL level -- we'll focus on the picks dealt prior to selection.

Leading into the playoffs in the 2007-08 season, Shero dealt a 2008 first-round pick (along with Colby Armstrong, Erik Christensen and Esposito) to Atlanta for Hossa and Pascal Dupuis, and sent a second- and fifth-rounder to Toronto for Hal Gill. In 2010, they dealt another second-rounder in exchange for Jordan Leopold. While the equivalent value of a No. 29, No. 50 and No. 60 overall pick is about the same as a No. 5 overall pick, those players contributed to the campaigns during which Pittsburgh reached the Stanley Cup finals or their Cup win in 2009.

The first-round pick Shero dealt for Iginla in 2013 (which the Flames then used on Morgan Klimchuk) or the two second-rounders he dealt for Douglas Murray may come back to bite Pittsburgh (the Sharks used one of the picks to move up and take Mirco Mueller in 2013). But for now, it seems the draft picks he moved were a reasonable price to pay to strengthen a legitimate Cup contender; moreover, the prospects he moved have been mostly underwhelming thus far.

Playoff performance

The Penguins cited their recent failure in the playoffs as a major reason for Shero's departure. Hockey can be a cruel sport due to the low-scoring nature of the game, making luck a factor in outcomes. However, the Penguins’ Corsi -- or puck possession percentage -- during the past three postseasons is better than one finalist (Boston) and one Cup champion (Los Angeles), and ranks third overall (for teams with a minimum of 15 games played). As we know, puck possession has been shown to have a positive correlation to team success.

The following table uses figures at even-strength with the score close in games from the 2012, 2013 and 2014 postseasons (data current as of May 17):

The Penguins’ goaltending issue is a notable one. Marc-Andre Fleury is a mediocre starting goaltender at best, but so much of goaltending in small samples like the playoffs is due to randomness. Put another way, even if a team gets 53 percent of the scoring chances in a seven-game series (assuming equal talent at goalie), they would still lose that series 40 percent of the time. The final column, PDO, is an illustration of each team's luck -- a rate of 1.00 is average, with anything above lucky and anything below unlucky -- so the Penguins have been around the average over this span.

The Penguins didn't play great at even strength in the regular season in terms of puck possession, but they were also devastated by injuries, whether looking at total man games lost or adjusting for cap-hit numbers, as seen here (courtesy of Springing Malik).

This is still a very strong team, which has had some unfortunate playoff results -- including giving up 3-1 series leads -- but is likely to have strong playoff results going into the future.

What does Shero’s replacement do now?

There could certainly have been other factors at play, but as we’ve often seen in professional sports, this was likely a knee-jerk reaction to a series of short-term results (five years of playoff results is a short-term sample in terms of number of games played) and drafting. The Penguins are a very good team due to their superstar talent, but their depth can be exposed during a run of significant injuries. Even so, they will probably continue be successful in the near term.

On the other hand, their development system is below average overall with the graduation of Maatta. While it is still strong in defenseman prospects, their top forward in the system is Sundqvist, who is a decent but not great prospect. They’ll likely want to target that area in the upcoming draft.

The best forwards available when Pittsburgh will be selecting in this year's draft (No. 22 overall) likely won't be ready to play in the NHL in the immediate future. But the players likely to be available in that range who could arrive the quickest would be those with professional experience like Jakub Vrana (Linkopings, SHL) or Adrian Kempe (Modo, SHL), as well as late-birth-date players like Nikita Scherbak (Dec. 30, 1995) or Nikolai Goldobin (Oct. 7, 1995).

The lack of talented young drafted forwards wasn’t the main reason behind the Penguins’ playoff failures, but if the incoming GM wants to address that area immediately, those prospects could be a good place to start.