AFM RSS Feed Follow Us on Twitter       
AMERICAN FOOTBALL MONTHLY THE #1 RESOURCE FOR FOOTBALL COACHES
ABOUT |  CONTACT |  ADVERTISE |  HELP  



   User Name    Password 
      Password Help





Article Categories


AFM Magazine

AFM Magazine


Variables 101 – Knowing how to analyze over 100 offensive variables gives your defense a statistical edge.

by: Brian Fleury
Defensive Backs Coach and Special Teams Coordinator, Towson University
© More from this issue

Click for Printer Friendly Version          

Knowing how to analyze over 100 offensive variables gives your defense a statistical edge.

Every defensive coordinator has his own style and process in preparing a game plan for the next opponent. Part of this process is detailing the statistical side of probability on the opponent’s play selection. Ideally, each defensive call has the probability of being successful, helps create one-on-one favorable match-ups and allows the players to execute the proper techniques in stopping the offense. If two out of these three criteria are met on each play, it will usually be a successful play for the defense.

GAME PLAN PROCESS

The first step in formulating an effective game plan is the analysis of raw data. In order for the process to be efficient, it is important that all data is accurate, especially in situations where the amount of plays is limited. In a small sample set, a single mislabeled play will alter the percentages by tens and skew the statistics. Therefore, ensuring the data is accurate prior to analysis is critical.

When performing any sort of data analysis it is also important to understand the variables and how they interact with each other. Different combinations of variables in different order will give a varying array of percentages. For the purposes of defensive game planning, there are five variables that are considered “Primary Variables”. They are:

1.  Field position

2.  Down and distance (D and D)

3.  Personnel

4.  Time on clock

5.  Score of game

These variables encompass all the relevant information that a defensive play caller is guaranteed to have prior to each play. The interaction of these variables creates a web of probability that when properly analyzed can give the defensive play caller insight into the offensive play caller’s tendency to select a run or pass in certain typical situations. In some situations it can give the defensive play caller and idea as to the specific scheme that will be used by the offense.

Beyond the primary variables, there are secondary variables that should also be analyzed. These variables provide information that is not guaranteed to be obtained prior to the snap and, therefore, is typically not used to determine the initial defensive play selection.  These variables include:

1.  Formation

2.  Backfield set

3.  Shifts and motions

4.  Formation strength relative to hash

5.  Displacement of eligible receivers

6.  Positioning of specific personnel
(e.g., #80 in the slot position)

These variables are typically used to formulate a system of “Checks and Audibles” for the defensive game plan. The information provided from analyzing these variables along with the primary variables can provide the opportunity for the defensive players on the field to anticipate a specific offensive play and either make a slight adjustment to gain a physical advantage, or “check” the defensive call to one that gives them a schematic advantage. These tendencies should always be analyzed and considered. However,  “Checks and Audibles” in a defensive game plan typically requires an advanced level of knowledge and savvy on the part of the players who are being asked to execute the game plan and may not always be utilized.

Finally, there are ‘Tertiary Variables’ that can be used similar to secondary variables. But they are not typically used in traditional data analysis. Tertiary variables are identified through intensive film study and are not always present. Some examples of these variables include:

1.  Offensive linemen stance (2pt/3pt)

2.  Offensive linemen splits and levels

3.  Receiver splits and levels

4.  Receiver stance (outside/inside foot up)

5.  Running back splits and levels

6.  Pre-snap gestures

In some instances, the identification of these variables can provide a defensive player with insight as to the scheme of the next offensive play. The potential for this advantage makes it necessary to consider these variables when formulating the defensive game plan.

DATA ANALYSIS

Understanding the primary variables and their interaction with each other is critical to effective data analysis in formulating a defensive game plan. The variables will only generate relevant data when arranged properly with each situation. For example, on 1st and 10, personnel will be the primary variable that most accurately dictates the run/pass or play selection tendency of the offensive play caller. However, on 3rd and 15, the D and D takes precedent over personnel in dictating the tendencies of the offensive play caller. Furthermore, less than one minute to play in the fourth quarter and a deficit of six points, take precedent over D and D and personnel in that situation. Not arranging the variables in order of importance will provide the defensive play caller with incomplete data and leads to poor play selection. In order to properly arrange the variables, it is important to define what a “normal” situation is. This means that when in a “normal” situation, the variable is not the primary factor impacting the offensive play caller’s selection.  For the purposes of this discussion, we will use the following values for the “normal” range:

1.  Field position = between -10 and +25

2.  D and D = 1st and 10 or 2nd and med (3-6)

3.  Time on clock = greater than 2:00 left in 2nd or 4th quarter

4.  Score of game = lead/deficit is less than 21 points

With all other variables in a “normal” state, personnel will be the primary variable used to determine offensive tendencies. Once one of the variables enters an “abnormal” state, the data must be analyzed in multiple arrangements to determine the philosophy of the offensive play caller and plan for the appropriate scenario as it applies to that particular opponent.

For example, a 2nd and short situation may be viewed as a choice down (2nd and short run/pass percentage consistent with overall R/P percentage) for some offensive play callers, and it may be seen as an opportunity to take a shot at a big play for some others, as indicated by a significantly higher pass percentage. If 2nd and short is determined to be a choice down, then personnel remains the primary variable used to establish the tendencies. If 2nd and short is determined to have a significantly higher pass percentage, then the D and D overrides personnel as a means to ascertain the R/P and play selection tendencies for that particular offensive play caller.


This example highlights the need to analyze the data in multiple forms in order to determine which percentages are most relevant to a particular offensive play caller, and, hopefully obtain an indication as to his play calling philosophy in any given situation. This process requires that we examine the following data reports containing primary variables on a weekly basis (in order to consolidate the data, D and D and Field Zone are grouped into relevant sub-categories; i.e., short, medium, long, red zone, grey zone, etc.):

1.  Overall R/P

2.  R/P by personnel

3.  R/P by D and D

4.  R/P by field zone

5.  R/P by 2-minute

6.  R/P by 21 point lead/deficit

7.  Overall play selection by R/P

8.  Play selection by personnel

9.  Play selection by D and D

10.  Play selection by field zone

11.  Play selection by two-minute

12.  Play selection by 21 point lead/deficit

13.  R/P by personnel by D and D

14.  R/P by personnel by field zone

15.  R/P by personnel by two-minute

16.  R/P by personnel by 21 point lead/deficit

17.  Play selection by personnel by D and D

18.  Play selection by personnel by field zone

19.  Play selection by personnel by two-minute

20.  Play selection by personnel by 21 point lead/deficit

21.  R/P by D and D by field zone

22.  R/P by D and D by two-minute

23.  R/P by D and D by 21-point lead/deficit

24.  Play selection by D and D by field zone

25.  Play selection by D and D by two-minute

26.  Play selection by D and D by 21-point lead/deficit

27.  R/P by personnel by D and D by field zone

28.  R/P by personnel by D and D by two-minute

29.  R/P by personnel by D and D by 21-point lead/deficit

30.  Play selection by personnel by D and D by field zone

31.  Play selection by personnel by D and D by two-minute

32.  Play selection by personnel by D and D by 21-point lead/deficit

33.  R/P by field zone by two-minute

34.  R/P by field zone by 21-point lead/deficit

35.  Play selection by field zone by two-minute

36.  Play selection by field zone by 21-point lead/deficit

37.  R/P by D and D by field zone by two-minute

38.  R/P by D and D by field zone by 21-point lead/deficit

39.  Play selection by D and D by field zone by two-minute

40.  Play selection by D and D by field zone by 21 point lead/deficit

41.  R/P by personnel by field zone by two-minute

42.  R/P by personnel by field zone by 21-pont lead/deficit

43.  Play selection by personnel by field zone by two-minute

44.  Play selection by personnel by field zone by 21-point lead/deficit

Note that we never progress beyond three active variables. The data becomes too diluted.

The data contained in these reports will be analyzed along with detailed film study to compile a game plan that gives us a schematic advantage in the appropriate situations. Once the tendencies have been determined for both run/pass and play selection within each situation, we will choose the defensive calls from our menu that schematically give us the greatest chance of success against the schemes we will most likely see. These defensive calls will be divided into two categories – base defenses with stunts (3 or 4-man rush) and pressures (5+ man rush).

In situations where the opponent tends to run the ball 40% or more of the time, we will choose defenses best suited to stop the run while maintaining the integrity of our pass defense. The base defenses will utilize stunts designed to attack the blocking schemes of the opponent’s favorite run plays combined with coverages that tend to give us a numerical advantage and allow us to cancel every offensive gap. The pressures will be selected based on their ability to attack the offense where they are likely to be running the football while maintaining integrity against less likely plays.

In situations where the opponent tends to pass the ball 61% or more of the time, we will choose defenses best suited to stop the pass. The base defenses will utilize coverages designed to give us the best chance for success against their favorite route combinations while using stunts that allow us to stress the protection scheme being utilized by the offense. The pressures will be selected based on their ability to attack the protections and threaten the quarterback while utilizing coverages that give us the best chance for success against their favorite route combination.

As a general rule, the game plan is formulated with the intent on stopping the run first. This is why we continue to focus on stopping the run in situations where the offensive tendency is to throw 60% of the time. In these situations, both base and pressure defenses will be selected based on their ability to stop the probable runs. Notice that on passing downs, the priority in base defense is to cover the routes and the priority in pressure defense is to threaten the quarterback.

Selection of base defense vs. pressure on passing downs is typically based on the ability of the opposing QB in three categories. Does he have a strong arm? Is he intelligent or does he make good decisions in the pass game? Is he accurate with his passing? Keep in mind that we might evaluate an opposing quarterback to be strong in any combination of the three categories, or deficient in any of the three categories. In situations where a deficiency is not present, we will plan to attack the opposing quarterback with whatever we feel we execute the best. The philosophy surrounding this thought process is best illustrated by the diagram above.         For example, if a QB is deemed to be accurate and intelligent, but does not have a strong arm, we would plan to utilize more 8-man drop coverage in an effort to limit the amount of space there is for the quarterback to fit the throw. The combination of smaller throwing lanes and increased flight of the ball due to the lack of arm strength should allow for more disrupted passes. The variable that changes this philosophy is always the ability of the quarterback to extend the play by running the football. This will typically limit the amount of man coverage played by the defense and significantly decrease the number of available huddle calls.

We will also examine the following data reports containing both primary and secondary variables:

1.  R/P by formation

2.  Play selection by formation

3.  R/P by formation by personnel

4.  Play selection by formation by personnel

5.  R/P by backfield set

6.  Play selection by backfield set

7.  R/P by backfield set by formation

8.  Play selection by backfield set by formation

9.  R/P by backfield set by formation by personnel

10.  Play selection by backfield set by formation by personnel

11.  R/P by shifts and motions

12.  Play selection by shifts and motions

13.  R/P by formation strength relative to hash

14.  Play selection by formation strength relative to hash

15.  R/P by displacement of eligible receivers

16.  Play selection by displacement of eligible receivers

This data will be analyzed along with intensive film study to determine if the defensive play caller would like to utilize any “Checks and Audibles” for the particular game. Typically, a R/P or play selection tendency has to be greater than 85% in order to justify the investment in a “Check” or “Audible” for that situation. In many cases, it is better to advise the players of any relevant tendencies and allow them to anticipate the selected offensive play giving them a physical advantage, rather than investing in a “Check” or “Audible”. The same holds true of any tendency derived from evaluation of the tertiary variables.

Finally, there are certain “Special Situations” which may lend themselves to create specific tendencies on the part of the offensive play caller. These situations are based on a variety of variables typically extending beyond the three-variable maximum utilized in general game planning. They do, however, tend to establish tendencies worthy of consideration in the defensive game plan. There are also potential personnel tendencies which are analyzed and may provide insight as to the offensive play caller’s general game philosophy. If broken down properly, these tendencies can typically be viewed in the following reports:

1.  R/P on 2nd and 10 after an incomplete pass

2.  Play selection on 2nd & 10 after an incomplete pass

3.  R/P on 3rd down after a sack

4.  Play selection on 3rd down after a sack

5.  R/P on possession and 10 after a turnover

6.  Play selection on possession and 10 after a turnover

7.  R/P on possession and 10 of the half

8.  Play selection on possession and 10 of the half

9.  Gadget plays

10.  R/P after a successful gadget play

11.  Play selection after a successful gadget play

12.  R/P after a failed gadget play

13.  Play selection after a failed gadget play

14.  Passes attempted by pass zone

15.  Receptions by position by formation

16.  Receptions by player

17.  Runs by position

18.  Runs by position by formation

19.  Runs by player

20.  Overall touches by position per game

21.  Overall touches by player per game

22.  Average yards per touch by player

These reports generate information that may only apply to one play throughout the game. However, the information should be analyzed and understood so the defensive play caller is prepared with a defensive call if the situation presents itself.

Once the data analysis is complete, we should have a list of base and pressure huddle calls prepared for the most prominent situations and tendencies provided by the data. The amount of huddle calls for each situation should be relative to the ratio of occurrence per game for that situation. For example, there will be significantly more huddle calls available for normal situations than there will be for 2nd and long with the ball on the -2 yard line. It is also important to understand that the goal of a defensive game plan is to force the offensive play caller out of his comfort zone and, therefore, force the offense to do something it is not accustomed to in order to win the game. With this in mind, the defensive game plan should provide the best opportunity to stop the offense’s 3-5 favorite runs or passes in any given situation. If the opponent broke a 50-yard run, but only ran this particular play once in five games, the defensive play caller should not be including a defense in the game plan that stops that play, but may be weak against the play they run 10 times a game in a similar situation. This requires great discipline on the part of the defensive coordinator, but is necessary in order to guarantee the efficient use of time in the staff room and at practice.

DETERMINING THE FAVORABLE MATCHUPS

Once the data has been analyzed and the film has been reviewed, it is important for the defensive staff to discuss the ability of the opponent’s personnel in comparison to its own personnel. Efficient data analysis aids the defensive play caller in formulating a game plan that, based on probability and statistics, should give the defense a schematic advantage.

Once this is completed, it is important to review the possible defensive huddle calls against the 3-5 favorite runs and passes in any given situation and discuss the potential one-on-one matchups that will result from the clash of the two opposing schemes. Generally speaking, any defensive call that may potentially result in significant amount of favorable matchups for the defense should be highlighted. Conversely, any defensive call that may result in a significant amount of unfavorable matchups should potentially be removed from the game plan.

It is important to recognize that this process is largely subjective and requires careful consideration on the part of the defensive staff. Suppose a defensive call presents extremely favorable matchups against all of the offense’s plays except the one they run the most. The decision to carry, and ultimately call the play in a game situation is that of the defensive play caller and is based on his capability to evaluate his own defensive players compared to the opponent’s offensive players. The ability to influence the outcome of the game may often be found in a play caller’s efficiency in predicting favorable matchups for the defensive personnel and repeatedly putting them in a position to succeed.

DETERMINING WHAT THE DEFENSE DOES WELL

Similar to the evaluation of favorable one-on-one matchups is the discussion of what the defensive unit executes well. This process is typically less subjective and can be researched through statistical self-scout analysis and the grading of individual positions on particular defensive calls.

For example, if playing cover 2 gives the defense a schematic advantage in a given situation, but historically, the defense is giving up 10+ yards per pass attempt in cover 2, the defensive play caller may want to remove the call from the game plan. In addition, if the defensive coordinator knows that the players execute a certain pressure with great confidence, he may want to highlight the opportunities to call that pressure within the game plan. This philosophy extends beyond the team concept as well. A good coordinator will be aware of individual strengths and how they relate to defensive huddle calls.

For example, if a player is not an effective pass rusher, it will probably be more efficient to utilize him in coverage, even if he has a favorable one-on-one matchup in pass rush situations. Awareness of the strengths of the players adds another variable to the play selection process. However, these variables deserve consideration and can often be used to help the defense gain confidence over the course of a series or a game by putting the players in a position to utilize their strengths and experience success.

FINAL EVALUATION

Once the game plan has been refined, it is important to continue to evaluate the effectiveness of the potential play calls during practice. When planning practice, the coordinator should maintain awareness of the probability of certain situations occurring as well as the preferred ratio of pressure to base defense. These ratios should be maintained in preparation.

In other words, if you plan to pressure 65% of the time in games, you should pressure 65% of the time in practice. The same is true of other situations as well. If 30 out of 75 snaps in a game are 1st and 10 (30/75 = 40%), then 40% of the reps in practice should be focused on defensive calls vs. offensive calls that will likely occur on 1st and 10. Over the course of the week, the coaching staff must evaluate the effectiveness of the defenses being utilized and potentially eliminate those that have proven unsuccessful in practice. If done efficiently, the game plan will be reduced and become more concise. The final product will be a list of calls for given situations that have a probability of providing a schematic advantage, while presenting favorable one-on-one matchups, and cultivating confidence over the course of the game.

CONCLUSION

The game planning process is a necessary means to an end. The attention to detail in the initial breakdown allows the opponent to be seen from many different angles. The data analysis allows the defensive play caller to evaluate and understand the opponent’s tendencies in certain situations. The analysis of strengths over weaknesses from both a personnel and team standpoint allows us to put ourselves in a position to be successful. All of this is important.

However, the defensive play caller must be cautious about paralysis by over analysis. It is impossible to call the perfect play for every situation. We take a mathematical approach to planning and come up with the best plan based on probability, but it is important to remember that there is always a human element that can, and will, deviate from the percentages and defeat the science. The goal is to study, absorb, and commit to memory as much information as possible over the course of the week. Know the plan, trust your own preparation, and at the end of the day go with your gut.






NEW BOOK!

AFM Videos Streaming Memberships Now Available Digital Download - 304 Pages of Football Forms for the Winning Coach



















HOME
MAGAZINE
SUBSCRIBE ONLINE COLUMNISTS COACHING VIDEOS


Copyright 2024, AmericanFootballMonthly.com
All Rights Reserved