Posts Tagged ‘draftmetrics’

Offense or Defense: What Do You Draft?

NFL draft

Quarterbacks always have the inside track when it comes to being selected at the top of the draft board. But that aside, do NFL teams favor one side of the ball or the other when drafting? Do teams prefer to load up at a position early in the draft and then ignore that position later

Quarterbacks always have the inside track when it comes to being selected at the top of the draft board. But that aside, do NFL teams favor one side of the ball or the other when drafting? Do teams prefer to load up at a position early in the draft and then ignore that position later in the draft, or vice versa? This article addresses those issues through the examination of the 2005 through 2014 drafts.

Offense vs. Defense

While there might be short-term fluctuations due to supply or demand at a position, over time it is reasonable to expect that number of offense players and defensive players drafted should be about even. When looking at the 2005-2014 drafts that does turn out to be the case. Of the 2501 non-kickers drafted, our count is that 1245 were offensive players and 1256 were defensive players. That’s about as even as you can get.

There are more significant variances on a team-by-team basis. Certain teams, even over a 10-year period, do show at least some indication of bias on one side of the ball or the other. A short-term bias is certainly understandable as a team looks to plug holes wherever they exist. Over a 10-year period, though, all that should even out and it may come to a team’s drafting strategy or pure chance.

The following table shows the percentage of offensive draftees for each NFL team for 2005-2014.

The ends of the spectrum are the Jets taking offensive players with 58% of its selections and, on the other end, the Falcons taking defensive players with 60% of its choices. Is the variance from the average a matter of a team’s strategy or is it just random based on a team’s draft board and the players available? It is impossible to say without being in the draft room or being part of a team’s management.

The first three rounds of the draft produce most of the starters in a draft class. Over those three rounds, the numbers historically lean slightly toward defense, but it is still a relatively even split with about 49% of the draftees being offensive players versus 51% on defense. The team distribution changes, though, indicating that some teams favor one side of the ball in the first three rounds and then the other side in the final four rounds. Here is the chart as previously shown, but for the first three rounds only and with the scale slightly changed to accommodate the 49%/51% split.

The extremes for the first three rounds are the 49ers with 59% of its selections from the offensive side and the Saints with defensive players making up 62% of its selections. The same question as above is still applicable regarding whether this is a planned strategy or just a matter of chance.

The differences by team can be seen more clearly in the next table. This table shows the percentage of offensive draftees by playing position and team for round 1-3, rounds 4-7 and overall. Defensive draftees are, of course, 100% minus the percentage of offensive draftees.

Bias by Playing Position

 Within the offensive and defensive splits presented above, there are also biases by playing position. Before looking at the information by team here is a breakdown by playing position for the first three rounds, the last four rounds and all rounds. The percentages represent the portion of all drafted players in each grouping from 2005-2014.

This table shows that quarterbacks, wide receivers, defensive linemen and corners account for 50% of draftees in the first three rounds but only 44% of players drafted in rounds 4-7. This indicates a bias towards drafting those positions in the top three rounds.

To get a better feel for the teams that are most and least likely to draft players at those four positions, the following tables show the distribution of players drafted by playing position and NFL team.

The first table shows the quarterbacks drafted in the first three rounds. The Browns, still searching for a quarterback, had the most with five. Six teams did not draft a quarterback in the first three rounds. The Texans are one of those six, though they are not settled at the position.

The next table shows the distribution by team for wide receivers drafted in the first three rounds. The Giants and Titans are the leaders with eight and seven, respectively. The Titans are far from settled at the position. Five teams drafted two or fewer receivers in the first three rounds. With the exception of the Cowboys, none of the teams are well set at the position.

The next table shows the distribution for defensive linemen. The Eagles had the most with 10 and the Redskins the least with one.

And finally, the distribution for corner backs is shown in the next table. The Rams led with eight corners drafted in the first three rounds while the Eagles had only one.

This addressed only one aspect of the positional bias issue. A “shortcut” way of looking at the possible existence of a bias is to find situations where the number of players drafted at a position is somewhat greater (or less) than 1.5 times the number of draftees for the first three rounds. The 1.5 factor is based on averages by position as discovered in this study.

 

The logic would be applied as follows:

  • The 49ers selected eight offensive linemen in the first three rounds and six offensive linemen in rounds 4-7.
  • This indicates a bias for selecting offensive linemen earlier rather than later as using the 1.5 factor they would be expected to have drafted 12 lineman in rounds 4-7, or double the number drafted.
  • On the other hand they selected two corners in rounds 1-3 and nine corners in rounds 4-7.
  • This would indicate that they believe they can find corners later in the draft and do not need to draft them early.
  • The expectation would be that three corners would have been selected in the later rounds, and not the nine actually selected.

The following table shows selected instances of positional biases for each NFL team and the number of players drafted in rounds 1-3 and then in round 4-7.. The number of instances was capped at three. The column labeled “bias” indicates whether the bias was in favor of drafting a position early (like the 49ers offensive linemen) or in favor of drafting a position later. 1-3 indicates that the bias is toward drafting early. 4-7 means that the bias is toward drafting later.

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Rankings of NFL Teams by Draft Class

NFL draft

For all the talk about the draft and teams that do well, there is one point that must be stressed. No team does well in the draft every year. Taking that statement to the next logical step, a team does not have to do well in the draft every year to be successful.

To study

For all the talk about the draft and teams that do well, there is one point that must be stressed. No team does well in the draft every year. Taking that statement to the next logical step, a team does not have to do well in the draft every year to be successful.

To study this premise and associated issues, we reviewed drafts from 2005 through 2012. The drafts from 2013 and 2014 were omitted because it is too soon to make even a preliminary judgment on those. Before discussing the results we should discuss the key elements of the study.

First, contrary to most of the other studies we have done, only a player’s career with the team that drafted him is considered. For example, the Jets do not receive credit for the years Darrelle Revis spent with the Bucs and the Patriots.

Second, despite considerable thought on the matter, we could not come up with a formula or measure that would yield a meaningful comparative rating for the teams, so the ratings are subjective based on several factors. These factors include:

  • The number of two-year starters in a draft class
    • The cut-off of two years was used so that we could include as many current drafts as possible
  • The number of games started by a player over the course of their career with the team that drafted him
  • The number of Pro Bowl selections
  • The number of All Pro selections

It is acknowledged that there is an inherent advantage in being drafted by a “bad” team as the path to a starting job is likely to be an easier one, but this was not considered in the rankings. Draft position and number of choices were also not considered, so the result is an absolute and not relative grade.

Based on these factors the drafts of each team for each draft class were analyzed with the teams ranked one through 32. The full rankings are shown at the end of this article. It is recognized that the rankings for at least some of the years might change over time as careers ebb and flow. One would expect, for example, that more post-season honors are likely to be won in the future by some of the more recent draftees.

Perhaps the most striking results from the study is that no team was ranked #1 more than once. Similarly, no team was ranked last more than once either. While other factors may be at play, this supports the variability of draft results and the presence of the “luck factor” in the draft process. The same management team following the same process can garner different results in different years.

Seven teams were ranked in the top 10 in at least half of the eight drafts. Those teams, with its ranking based on its won-lost record for 2005-2014 in parentheses, are:

Several things stand out in the analysis:

  • The Packers were actually ranked in the top 10 in five of the first six years of the study before earning lower rankings in 2011 and 2012
    • The Packers have been in either the top or bottom 10 in each of the eight drafts
  • The Seahawks have finished in the top three in the 2010-2012 drafts
    • They are the only team with three top three grades
  • The 49ers were ranked in the top 10 in each draft from 2005-2007 but only once since then
  • Neither the Chargers nor the Raiders had even one top 10 grade
    • The Raiders had only one bottom ten grade as well
  • The Patriots, with the top won-lost record for 2005-2014 by a comfortable margin, were in the middle of the pack as far as draft grades with three top 10 rankings and three rankings in the bottom 10

Seven teams finished in the bottom ten at least half the time. These teams were:

A few notes about the teams finishing at or near the bottom:

  • The Saints have finished in the bottom 10 for each of the last four drafts
  • The Jaguars and Giants have finished in the bottom 10 for each of the last three drafts
  • In addition to its four bottom 10 grades, the Bears have ranked 11th from the bottom on two other occasions
  • Every team but the Titans have finished in the bottom ten at least once

Here are the complete annual rankings for the 2005-2012 drafts:

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Which NFL Teams Draft the Best?

NFL draft

Evaluating the draft performance of an NFL team is difficult at best. The ultimate test of a team occurs on the field, of course, and is a mixture of many elements, with draft performance being just one. There are a number of issues when trying to isolate draft performance. Teams do not have the same

Evaluating the draft performance of an NFL team is difficult at best. The ultimate test of a team occurs on the field, of course, and is a mixture of many elements, with draft performance being just one. There are a number of issues when trying to isolate draft performance. Teams do not have the same number of selections, drafted players are moving into different playing situations, and so forth.

In this article, the number of starts from 2005 through 2014 was used as the most reasonable metric for measuring draft performance. This is not perfect but allows a window into draft performance. Starts for a player are credited to the team that drafted him and includes games started for either the drafting team or a subsequent team. Drafts for the past ten years (2005-2014) were studied to see what conclusions could be drawn.

Each NFL team starts with 70 selections for the 10-year period (10 years and one selection by round). Adjustments are then made for selections lost due to penalty or used in the supplemental draft, compensatory selections awarded and the net number of choices gained or lost through trades (mostly trade-up or trade-down transactions). Here is a summary by team, sorted by total number of selections between 2005 and 2014:

There is quite a range in the number of selections with the Saints having the fewest with 60 and the Packers the most with 96. All draft selections are not created equal, however, as a first round choice is worth considerably more than a seventh round selection. It is fair to say, in my opinion, that no one views the absolute number of starts as being fully indicative of a team’s expectations.

A measure that does a better job of weighting the draft choices is the number of starts a team could historically expect, given their number of selections and the location of their selections. This sets the expectation but does not provide any information about actual results. The following ranks the NFL teams by the number of expected starts for players drafted from 2005 through 2014.

The revised rankings push the Rams into the position of being the team that should have expected the most help from the draft over the past 10 years, with the Packers dropping from first to second. There is little change at both the top and the bottom of the expectations between the first and second tables.

We next ranked the teams by the actual number of starts by players drafted by each team in the 10-year study period. This gives great weight to the total number of selections by a team, particularly early round selections. The following table shows those rankings:

As can be seen from reviewing the previous two tables, the difference between actual and expected performance can be rather significant. The Ravens, for example, are ranked fifth in actual starts compared to 18th in expected starts by players selected in the study period.

The above table still places, in my opinion, too much weight on the actual number of draft choices. What I believe to be preferable is to rank the teams by number of actual starts as a percentage of expected starts. The following table shows the percentage by which a team’s actual performance exceeds or lags expected performance. Players drafted by the Seahawks, for example, had almost 19% more games started (1785 divided by 1505) than a historical analysis would suggest. A number in parentheses indicates that a team did not achieve expectations.

It is interesting that this year’s Super Bowl participants (Seahawks and Patriots) are at the opposite end of the ratings. This reinforces the notion that there is more than one way to achieve NFL success.

The Seahawks achieved most of its success in rounds two through four, while being close to average in other rounds. The Patriots did better than expected in round one but were ahead of only the Lions in second round performance. The first round is the only round where the Patriots exceeded expectations by more than a nominal amount. While the Patriots did draft some very fine players in round two (like Rob Gronkowski, Sebastian Vollmer and Jamie Collins), they also had their share of flops and players approaching flop status in Ras-I Dowling, Darius Butler, Terrence Wheatley, Ron Brace, Tavon Wilson and Chad Jackson.

The best and worst performances by draft round are shown in the following table. All situations where actual was better or worse than expected by at least 100 starts are included. The table indicates that the Colts’ sixth-round selections, in the aggregate for the ten-year study period, exceeded expectations by 264 starts.

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Comparing Draft Years

NFL draft

Every year experts offer up their opinions on the upcoming draft, both on the overall depth of the class and the quality and depth by playing position. In this article we will explore how real these differences are and the degree of difference among draft years.

Year-to-Year Comparison

What is the best way to measure

Every year experts offer up their opinions on the upcoming draft, both on the overall depth of the class and the quality and depth by playing position. In this article we will explore how real these differences are and the degree of difference among draft years.

Year-to-Year Comparison

What is the best way to measure the differences? There is no perfect metric, but the most practical performance metric is the number of games started. Number of starts has the principal advantage of letting us use recent years in the analysis whereas other measures (such as number of five-year starters) required us to cut off the analysis well before the most recent drafts.

There is an inherent conflict between using current information versus complete information. It takes 15 years or so to “complete the book” on a draft class. This would mean that the most recent year that could be used in this analysis is 1999. That serves as a sound basis for the analysis but many readers would regard the information as stale and, therefore, not relevant.

It was decided to compare draft classes after their first, third, fifth and seventh years. The draft years used were the most recent 10 drafts for which the number of starts data was available as follows:

The following table summarizes the data by draft class for each of the four time periods. The “ratio” row represents the ratio of the number of starts for best draft compared to the worst draft. A high number shows a lot of variation and a low number shows little variability.

This table shows that the degree of difference, as expressed by the ratio, is greatest for the first year and levels off after that. The 2006 draft year has held up best over time. The draft class in each of the last four years has exceeded the number of first-year starts from 2006 but both 2011 and 2012 have fallen behind 2006 by the end of the third year and it is too soon to tell for 2013 and 2014. It remains to be seen if the advantage of the 2006 draft class will hold up.

The 2008 draft class is also an interesting case. That class is ranked last in first year starts but moves up to the middle of the pack for the subsequent measurement periods. This reinforces the notion that the first year does not tell anywhere near the whole story when it comes to evaluating draft classes.

This analysis shows that there is a reasonably large difference among draft years. This makes characterizing draft classes as good and bad a logical exercise.

As an aside, data from the draft classes that are virtually complete as far as number of starters (1995-1999) is instructive regarding the evolution of the impact of a draft class. The cumulative average percentage of total starts by year for the five draft classes is shown in the following table. The table tells us that 91% of the starts from a draft class occur in the first 10 years.Playing Position Comparison

It should be no surprise that the level of variability increases by playing position. There are fewer data points and this leads to greater variances in results. The analysis by playing position was confined to the most recent ten draft classes and excluded fullbacks and special teams players. Again, the number of starts was used as the performance metric.

The following table shows the best and worst classes for each playing position after one season by draft class.

This table shows that there significant differences among playing positions with the offensive line and defensive backs showing the smallest, though still significant, differences.

The next table shows the same information after three years for each playing position by draft class (which excludes the 2013 and 2014 draft classes).

This table shows that the ratios have tightened significantly by the third year but that they still exist. Offensive linemen show the smallest difference between the best and worst year with running backs having the largest difference.

It is interesting to note that while 2006 is a highly rated draft class, it does not appear as the best year for any playing position.

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The Rest of the Equation

Andrew Luck

The article “Draft Probabilities by Playing Position” laid out the probabilities of achieving various milestones for players selected in the NFL draft. What was missing from that discussion, though, is the time element. That is, how long does it take a drafted player to become a starter or achieve another relevant milestone?

When a

The article “Draft Probabilities by Playing Position” laid out the probabilities of achieving various milestones for players selected in the NFL draft. What was missing from that discussion, though, is the time element. That is, how long does it take a drafted player to become a starter or achieve another relevant milestone?

When a team signs a free agent there is a general expectation, unless a special team player is signed, that he will move right in and be helpful. For drafted players the expectations are generally lower in terms of providing immediate help. But what exactly should those expectations be?

Three milestones were used to measure the time element for the purposes of this article. The milestones were the length of time used to become a one-year, three-year and five-year starter. Our definition of a starter is a player who starts at least eight games in a season. The averages include only the players who achieved those milestones. For example, take the case of a player who started for four years. He would be included in the one-year and three-year calculations but would be excluded from the five-year calculation.

The best “score” a player can earn is 1.0, indicating that he became a starter in his rookie season. He would receive a 2.0 if the becomes a starter in his second season. There are no partial seasons awarded, but the averages do show partial seasons (kind of like the Census Bureau saying there are 2.58 people per household).

The logical expectation is that players drafted earlier will start faster (and more often as indicted in the “Draft Probabilities by Playing Position” article). Whether this is because the players are better or because they get more chances due to being highly paid is a matter of debate. The truth is probably that it is a combination of the two.

The following table shows averages by playing position and Draft Range for the one-year milestone and indicates that about 42 players per season start as rookies. It is probably not surprising that running backs take the longest to start for any playing position among early round draftees. For the group a whole (as indicated by the “All” column), though, it is defensive linemen that take the longest to start their first season. The average for the rest of the positions are pretty close.

The table also confirms that the earlier a player is drafted, the sooner he will start. Players selected with the first four picks start much sooner than a player taken later in the draft.

The next table shows the averages for achieving the three-year milestone. Running backs again take the longest to start among the early round selections. This holds true through the 4th Draft Range (which is through the 46th pick). Overall, defensive linemen tend to take longer than average to achieve the three-year milestone. Offensive tackles and linebackers are at the other end of the spectrum and reach the milestone sooner than average. The amount of time to start for a third season ranges from 4.0 to 4.8 seasons.

The final milestone reviewed was the amount of time it takes a player to become a five-year starter. It is interesting that the range tends to narrow at this point because only the better players are likely to achieve this milestone and be included in the calculation of the average. The range is from 6.0-6.7 seasons, slightly narrower than the range by position for achieving the three-year milestone. Among the earliest draft selections (first 14 picks) Running Backs and Quarterbacks tend to take the longest to reach the milestone. Offensive Tackles drafted in that same range are the fastest to reach the five-year milestone. Overall, Guards and Offensive Tackles are the fastest to reach the milestone, while Defensive Ends and Quarterbacks are the slowest.

Click here for the complete breakdown of “Draft Ranges”

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