Consistency value, often abbreviated as CV, is a fantasy football statistic used to measure the reliability of a player for a given season. CV calculations are generally only conducted for "start worthy" players, real-life starters that score enough weekly points to merit fantasy consideration.
Patrick Mahomes (QB, Kansas City Chiefs) had the highest consistency value of all eligible players for the 2018 season (0.259).
The first step in calculating a player's consistency value is to find the player's average fantasy points per game for the entirety of the season.
Ex. If the player's total fantasy point output was 304 over the course of 16 games played, the number of fantasy points scored on average would be 304/16 = 19 points per game.
The next step is to calculate the player's weekly standard deviation, which is a measurement of how far away each week's point output was from the average number of fantasy points scored per game. This is done by finding the difference between the average points scored per game and each of the 16 weekly scoring totals. The square root of the remaining value is the standard deviation.
The final step is to divide the standard deviation by the average points per game (SD/APP). The figure that remains represents the player's consistency value for the season.
When trying to analyze CV values, it is important to note that the lower the CV, the more consistent the player. In other words, a player with a consistency value of 0.3 can be relied upon to score close to the same number of points each week, whereas a player with a consistency value of 0.75 is far more sporadic and will likely have a few low-scoring games.