Analytics 101: What is Market Share?

Zach Crutcher (@ZackyNFL) The Lateral Contributor

A new series from The Lateral, our friend and math teacher extraordinaire Zacky will be breaking down some key analytics and what they all mean in order to help you win your fantasy football league. We begin with Market Share: Whether you are playing dynasty with the future in mind, bestball for that upside, or redraft just hoping to win it all, the common theme among successful teams is they generate additional value compared to their competitors. This goal can be accomplished in a number of different ways: you can have a strong draft, identify the right talents on the waiver wire, or gain value through trades. One way to improve your odds of success is learning how to see players who stand out in less than obvious ways. This is the idea behind market share and it was 2014 when Shawn Siegele of RotoViz first introduced the concept.  Market share (MS) is the process of taking an individual’s stat total and dividing it by their team’s combined stat total. It allows you to calculate an individual player’s percentage of receiving yards out of the yards their team had as a whole. You can use this for a variety of statistics other than just receiving yards as well! Receptions, targets, air yards, and even touchdowns are just a few examples that you can explore. While market share is not without its flaws (we will revisit this), it is a very useful metric. The primary goal of using market share statistics is to level the playing field between players-- similar to the idea of “per 36 minutes” stats in the NBA which you may be more familiar with.  Let’s start with an easy example for each of the two main ways that market share is used: comparing two wide receivers’ relative production in terms of their receiving yards and their touchdowns. In the 2019 season, Chase Claypool totaled 66 receptions, 1037 yards, and 13 touchdowns in 13 games for the University of Notre Dame. Michael Pittman Jr. put up 101 receptions, 1275 yards, and 11 touchdowns for USC in 13 games. At first glance, they are close enough and it would be tempting to give the edge to Pittman for earning himself an extra 35 receptions, 238 yards, and the same number of touchdowns. Before doing so, we can reexamine the two players through the lens of market share. As a team, USC threw for 4364 yards on 514 receptions with 35 passing touchdowns. Notre Dame threw for only 3277 yards on 416 receptions for 37 passing touchdowns.


Without the context that market share provides, some would be quick to assume that Pittman Jr. was superior to Claypool in terms of both receptions and receiving yards. Even in the 2020 NFL Draft, Pittman Jr. was taken 15 picks before Claypool at picks 34 and 49 respectively. Interestingly enough, we find that Chase Claypool was responsible for creating 31.64% of his team’s yards compared to a slightly lower 29.22% for Michael Pittman Jr.. Claypool also had a higher market share of his team’s passing touchdowns with 35.14% compared to Pittman Jr.’s 31.43%. Finding these subtle differences is a way to identify potential breakout candidates or increase the hit rates on your projections. One glaring issue with market share is that it does not accurately adjust for injuries or suspensions. This unfairly punishes players who miss multiple games and can lead to missing out on some of the biggest “value” picks. Let’s take a look at DK Metcalf, someone that has 31 teams wondering why they let him fall all the way to Seattle with the 64th pick in the 2019 NFL draft. Metcalf only played in 7 games during his final season at Ole Miss. In the 2018 season, Ole Miss had a total of 4157 receiving yards and Metcalf was responsible for 569 of those. If you remember our formula for market share receiving yards, it is: 


For Metcalf’s 2018 season that would give us a Market Share Receiving Yards of:


Nice. Or maybe not so nice. When trying to find values, we probably want to find players that reach a higher threshold. Perhaps it is unfair to count the receiving yards for a player in 7 games out but count the team’s total over 12 games. Let’s take a look at what happens if we adjust MS Receiving Yards to MS Receiving Yards per Game. 


Ole Miss averaged 346.42 receiving yards per game during the 2018 season. DK Metcalf himself averaged 81.29 receiving yards per game in his 7 stats:



Looking through this lens, we can see that Metcalf's MS Receiving Yards/Game would be:


This is significantly better, it is a percentage increase of about 71.4%, meaning we nearly doubled Metcalf’s market share by taking injuries and missed games into account. DK Metcalf appears to be significantly better than it seems when looking at the raw numbers. Looking at raw market share values and per game market share values is the best way to have a rounded approach. Neither method is perfect, so finding the right combination of both will help us improve our accuracy. While the raw Market Share values will be biased towards players who played more often (they say the best ability is availability!), MS per game values can be misleading due to outliers having a larger effect on the per game averages for small sample sizes. Let’s take a look at some of the wide receivers from the 2018-2020 draft classes through the lens of their Market Share Receiving Yards per Game in their rookie season as well as each player’s best MS Receiving Yards in college:


2020 


2019


2018


Combined MS Graph

(High and left = bad, Low and right = good).


What stands out to you? 

  • Justin Jefferson is really really good! Just wait until his former LSU teammate Ja’Marr Chase joins the fray.

  • Terry McLaurin posted an absurd 32.77% MS Rec.Yds per game as a rookie. If he gets a quarterback other than Alex Smith, he could finally cement himself as a top 12 wide receiver

  • Denzel Mims was more impressive than it may initially seem, posting a middle of the pack MS RecYds/G on an offense with significantly lower passing volume. Justin Fields or Zach Wilson could be the key to unlocking Mims’ as the alpha WR that he profiles as.

  • Brandon Aiyuk missed 4 games as a rookie, but in the games that he did play he was incredibly impressive, on par with CeeDee Lamb among others.

  • Despite QB issues and struggling with drops, Jerry Jeudy had a pretty good season and I am not concerned about him going into 2021.
In closing, market share is a way of leveling the playing field across the NFL or across college football. We can use this tool to help identify diamonds in the rough, the players that are responsible for high percentages of their teams offense. This is especially important if those offenses are not as prolific. Not every college player gets to suit up for Alabama or Ohio State, and finding which wide receivers can do more with less is a step in the right direction of evaluating talent more successfully. One player to keep your eye on is Rashod Bateman from Minnesota. Although he only played in 5 games for his junior season, Bateman put up 472 yards out of his team’s 1381 for a whopping 34.17% market share of receiving yards. Bateman played in 5 out of his team’s 7 games, and his market share of Receiving Yards/Game is an absurd 47.8%. Although Bateman’s stock continues to climb, he is a textbook example for the power of market share. What does market share lead us to? Dominator Rating, so stay tuned! Follow The Lateral on Twitter (@TheLateralFF)

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