Aaron Rodgers & Pre-Snap Motion

The use of motion has been one of the major trends facing defensive football in the past several years. Analytically, the use of motion by offenses has a distinct advantage. Defenses are reactionary in nature, so moving someone pre-snap can give the offense an edge or throw the defense off balance. Seth Walder, ESPN Sports Analytics, tweeted this about the Week 1 NFL usage of motion:

EPA/P is the average “Expected Points Added” divided by the number of plays. This stat illuminates how efficient an offense is as they go down the field. EPA as a stand-alone stat rates how many points an offense is expected to gain (or lose) depending on the yard line and Down & Distance. Each play is rated against where they started and where they finished. That number is the plays EPA. Since yards gained is a flawed stat, EPA uses expected points from historical data to calculate how effective the play was at creating scoring opportunities. Did you put money in the back or take it away? Defensively, this can be used to measure the effectiveness of calls during a drive.

For Week 2 usage rates, click HERE

Two types of motion are studied by analysts. Pre-snap shifts (everyone is set) and motion as the ball is snapped, or what ESPN refers to as “Snap Motion.” Shifts are when a player moves from one spot and establishes himself in another. He is not moving when the ball is snapped. Snap Motion is when the offensive player is moving horizontally as the ball is snapped.

Football is about leverage. Motion uses speed to leverage the defense. Since NFL defenses are so man heavy, it is not surprising that the use of Snap Motion has led to higher EPA/P success.

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