Terms Glossary

Basic Player Data

Value Over Stream (VOS) – The VOS metric calculates each player’s fantasy points per game above the average waiver wire replacement in standard fantasy league formats during either the current or previous season, depending on the time of year. VOS also incorporates a bust rate coefficient to throttle each player’s VOS according to the fragility and subsequent uncertainty of forecasting the annual fantasy point output of players at his position. By incorporating a volatility-related coefficient, VOS is the evolutionary next step in Value-based Drafting (VBD) and provide a helpful guidepost to be utilized during fantasy football drafts.

A comprehensive review of the rationale behind the VOS metric is available here: Introducing: Value Over Stream (VOS)

Hand Size – data presented by John Bales from Fantasy Labs showed a relationship between hand size and quarterback performance, particularly in cold weather conditions.Because of this positive correlation over a large sample size between hand size and productivity, hand size is a relevant, predictive attribute for quarterbacks.

Body Mass Index (BMI) – formerly referred to as the “Quetelet Index,” BMI dates to the 19th century and provides a simple numeric measure of a person’s thickness or thinness. Formula is as follows: Mass (lb) / Height (in)^2 x 703. Individuals with high BMIs tend to be built more like a bowling bowls, an ideal stature for an NFL running back. Therefore, BMI indicates a running back’s relative sturdiness.


Prospect Profile

College Dominator Rating – first outlined by Frank DuPont in the book Game Plan, the college dominator rating represents a player’s “market share” or his percentage of his team’s offensive production. For example, a 35+% dominator indicates that a wide receiver has the potential to be a team’s No. 1 WR and/or a high caliber contributor. 20-35% indicates a mid-level talent with situational upside. Less than 20% is a red flag.

For wide receivers and tight ends, the dominator rating is the percentage of team receiving production. For running backs, it is the percentage of total offensive production, because running backs are involved in both the running and passing game. College Dominator Rating is not relevant for the quarterback position.

Breakout Age – the younger a person is when he/she first becomes a leader in their respective field, the more likely that person is to go on to become *phenom*enal at their craft. Following this logic, Frank DuPont and Shawn Siegele first examined each wide receiver’s breakout age on RotoViz.com.

The breakout age for wide receivers is defined by their age at midpoint of the college football season when they first posted a Dominator Rating at or above 20% (unless an or other extenuating circumstances prevented the player from playing a full complement of offensive snaps). For tight ends and running backs, a 15% Dominator Rating is necessary to qualify for a breakout designation. Quarterback breakout ages are determined by their age when they first posted a QBR of 50 or higher in a college season, and quarterbacks must average 20 or more action plays per team game played to qualify.

In order to display a more granular percentile rank for comparison purposes, Breakout Ages are listed to the tenth decimal place.

Best Comparable Player – aggregates physical attributes, college production, workout metrics, and NFL productivity and efficiency (when available) to find each player’s most similar peer at his position.

40-yard Dash –for quarterbacks and tight ends, any 40-yard dash under 4.70 seconds is considered fast. Running backs and wide receivers are held to a different standard as times of 4.50 or below are considered fast for RBs and WRs.

Speed Score – Bill Barnwell first posited the metric in Pro Football Prospectus to better predict running back success. The formula is (weight*200) / (40-time^4). It factors weight into a player’s 40-yard dash time assigning a premium to fast times run by bigger, often stronger, running backs.

Height-adjusted Speed Score (HaSS) – first discussed by Shawn Siegele on his Money In The Banana Stand blog, it builds on Bill Barwell’s Speed Score concept to create a more relevant metric for wide receivers and tight ends. Unlike running backs, weight and height are correlated to wide receiver and tight end production, because height expands the player’s catch radius. HaSS layers height into the traditional speed score equation by also dividing the player’s height by the average wide receiver height: 73.0 inches (6’1”) or average tight end height: 76.4 inches (6’4 5/12’’). This results in a measure of a player’s speed that also incorporates a premium on both body weight and body length.

Agility Score – Agility Score is simply the sum of a player’s 20-Yard Short Shuttle time and 3-Cone Drill times. This number measures a player’s short area quickness and balance and correlates with an ability to avoid tackles and compile yards before contact.

Burst Score – indicates a player’s zero-inertia explosiveness (stop-and-start acceleration) and ability to catch the ball outside the body. Similar in concept to Agility Score, Burst Score sums a player’s Vertical Jump height and Broad Jump distance. Additionally, the metric is calibrated to give Vertical Jump and Broad Jump equal weight.

Catch Radius – first discussed by Scott Smith in a piece titled “The Catch Radius Project: In Search of Better TD Production”, the metric incorporates a player’s ability to cover ground as well as his ability to get vertical in order to score a player’s capacity to reaching the football in a 3-dimensional space. Catch Radius affects a player’s ability to succeed in the red zone, particularly on fade routes and 50-50 balls. The equation squares a player’s 40-time, 20-yard shuttle, and 3-cone and multiplies it by the square of a player’s height, arm length, and vertical jump. The values of all six data inputs are normalized to have equal weight.

Wonderlic Test – group intelligence test used to assess the aptitude of prospective employees for learning and problem-solving in a range of occupations. It consists of 50 multiple choice questions to be answered in 12 minutes. The best score in the history of the NFL was Harvard graduate Ryan Fitzpatrick’s 48. Athletes scoring in the 30-50 range are considered smart. Both Matt Ryan and Giovanni Carmazza scored a 32. Athletes in the 20-30 range possess solid functional intelligence. Both Ryan Leaf and Rich Gannon scored a 27. Scores under 20 indicate that a player may be challenged to process information on-the-fly. Both Dan Marino and Vince Young scored a 15. Blaine Gabbert crushed the Wonderlic with a score of 42, so he has that going for him.

SPARQ-x – An approximation of Nike’s SPARQ Rating (acronym it stands for: Speed, Power, Agility, Reaction and Quickness), a project started in 2004 to create a standardized test for athleticism similar to an SAT test for athletes. SPARQ input factors are 40-yard dash, vertical jump, 20-yard shuttle, and the power ball throw. Because Nikeʼs actual SPARQ formula is not public, we compared publically available SPARQ scores to their related input factors, reverse-engineered an approximation of the SPARQ formula, and then applied the formula to each playerʼs workout metrics. For calculation purposes, power ball throw was converted into bench press to ensure that all input factors aligned with specific NFL Scouting Combine events.

Athleticism Score – summarizes a player’s workout metrics and normalizes for size. It is derived by aggregating each player’s 40-yard Dash, Burst Score, and Agility Score, and then factors in a relevant measure of player size to ensure that big players receive a premium for speed, quickness and explosiveness. For QBs, PlayerProfiler adds a height premium. For RBs, we add a BMI premium. For WRs and TEs, we add a height and weight premium.

Percentile Rank– physical attributes and workout metrics include an overall percentile rank (100 being the best possible score) in parenthesis. The pool of players included in the percentile ranks consists of those currently signed to active and futures contracts.


Advanced On-field Stats and Metrics

Production Premium – isolates a player’s situation-agnostic efficiency. Production Premium compares the outcome of all pass attempts, carries, and targets to league-average outcome in those same game situations (yard line, down, and distance). Production Premium also takes into account time remaining and game score to account for non-standard situations such as 2-minute drills, clock-milking, and garbage time.

Positive values indicate that a player is more efficient than the average player, while negative values indicate that a player is less efficient than his peers with similar opportunities in similar situations.

Every player’s on-field performance is affected by his teammates. When a given player’s supporting cast changes (via trade or free agency), this metric is particularly helpful, because it measures that player’s capabilities across league-average situations.

Game Script – Average number of minutes a team is winning (positive value) or losing (negative value) during any given game of the season). Positive values indicate teams are often playing with a lead. Negative values indicates teams are more often playing from behind.

Opportunity Share – percentage of total team running back carries + targets for a particular back. Comparing Alfred Morris and Roy Helu’s 2013 usage help to illuminate the utility of this metric. Helu’s snap share was not significantly less than Morris’, but Washington gave the majority of opportunities to Morris, while Helu was asked to do a lot of blitz pickup work as opposing defenses relentlessly blitzed Robert Griffin III when Helu was on the field.

Juke Rate – isolates a running back’s elusiveness and tackle-breaking power by charting the number of broken, missed, and otherwise avoided tackles (displayed to the immediate left), and then dividing by the total number of touches (carries + receptions).

Yards Created – All yards above and beyond what was blocked. Yards created are generated by the runner after the first evaded tackle.

Air Yards – for quarterbacks, air yards are completed passing yards not including yards after the catch. The higher the percentage, the less a quarterback is being helped by his receivers gaining yards after the catch. For wide receivers and tight ends, air yards are total completed receiving yards from the line of scrimmage to the catch point. Air yards are also referred to as “completed air yards” elsewhere. On PlayerProfiler, air yards differs from total pass attempt distance and total target distance, which aggregates all completed and incomplete air yards.

Adjusted Yards Per Attempt (AY/A) – Modified yards per attempt incorporates a premium for touchdowns and a discount for interceptions. This stat was introduced and fully outlined in the book The Hidden Game of Football by Bob Carroll, Pete Palmer, and John Thorn.

Total QBR – Total QBR was developed by ESPN’s Stats & Information Group to measure the degree to which a quarterback contributed to scoring points for the team, and also to a win by the team. QBR adds a “clutch factor” to more traditional quarterback efficiency metrics. For example, it assigns a premium to a completed pass that earns a first down at the quarterback’s own 20-yard-line with 30 seconds left in the game. That completion may be unlikely to lead to any points for his team, but if the quarterback’s team is leading, it increases the win probability enabling the leading team to run out the clock.

Deep Balls – charts the total number of passing attempts that travel 20 yards or farther in the air. This metric is a window into the vertically-oriented nature of a quarterback’s offensive system. Quarterbacks with a high deep ball percentage generally play in vertical passing attacks as opposed to systems that emphasize short, quick passes.

Slot Rate – the percentage of passing down snaps a wide receiver or tight end lines up in the slot. To qualify as a slot receiver on any given play, a receiver must be lined up inside and covered up by a outside receiver in either three or four-receiver sets.

Route Participation – Indicates the percentage of total pass plays that the player ran a route in game when he was active.

Hog Rate – captures the rate of passing game utilization on a per play basis by calculating the number of targets per snap. This metric helps to identify wide receivers and tight ends with limited route trees that may have a low snap count and target share, but when they are on the field, are a focal point of the passing offense.

Target Share – measures the percentage of all passing targets directed at a particular wide receiver or tight end in games that that receiver was involved in the passing attack.

Red Zone Target Share – measures the percentage of all passing targets from a line of scrimmage at or inside the 20-yard line directed at a particular wide receiver or tight end in games that the receiver was involved in the passing attack.

Target Separation – A receiver’s average yards of separation from his assigned defender at the moment the pass arrives.

Target Distance – Total distance traveled by all intended targets. Target Distance may also be referred to as total target depth or air yards elsewhere. Average Target Distance may also be referred to a average depth of target elsewhere.

Target Premium – Rich Hribar coined the term Target Multiplier in an XN Sports Fantasy Football: 2013 WR Review article. Referred to here as Target Premium, it is the percentage of additional fantasy points per target that a wide receiver or tight end generates over and above the other pass receivers on his team. This metric is especially useful when examining the impact of a quarterback upgrade on a wide receiver’s future production.

Catch Rate – captures a player’s ability to secure to secure the football in all situations regardless of the level of difficulty by dividing the total receptions by total targets.

Burn Rate – Percentage of targets allowed in which the defensive back’s assigned receiver gained more than 5 yards of downfield separation.

Coverage Rating – an comprehensive cornerback efficiency metric incorporating target rate, pass break-ups, catch rate allowed, and fantasy points allowed per snap.

Snap Share – the percentage of total offensive plays that the player was on the field for his team.

Fantasy Points Per Game – the average number of fantasy points that a player has scored in game where he had a point scoring opportunity. In other words, for a particular game to count against his fantasy points per game, he must have had a passing attempt, carry, or target. The metric assumes 1 point for every ten yards rushing or receiving, 1 point for every 25 passing yards, 1 point per reception (PPR), and 4 points for quarterback passing touchdowns.

Fantasy Points Per Opportunity – measures running back fantasy points in the context of the player’s overall usage and playmaking prowess. The metric is calculated by dividing total fantasy points by the combined total of a running back’s carries and targets.

Fantasy Points Per Target – measures wide receiver and tight end fantasy points in the context of the player’s opportunities. The metric is calculated by dividing total fantasy points by total targets.

Fantasy Points Per Attempt – measures quarterback fantasy points in the context of passing opportunities by dividing total fantasy points by passing attempts.

Weekly Volatility – measures the level of week-to-week fantasy point scoring variance. Players with numbers higher than 8.0 have significant weekly output oscillation, and values over 10.0 indicate an extreme boom/bust range of outcomes.

High week-to-week volatility negatively impacts standard league formats that require lineups to be manually set each week. On the other hand, high volatility is preferred in “best-ball” formats that automatically set optimal weekly lineups.