Historical MLB Draft Team Grades. Clamoring fans may expect to get a…
By: David Hart
Tags: Mlb Draft, Sports, Baseball, Sports Analytics

Clamoring fans may expect to get a superstar player with every first round pick their team has, but clearly history has shown us that those can be rash expectations. In fact, many first round picks never take a single swing or throw a single pitch at the MLB level. So yes, while a team can get Alex Rodriguez #1 overall or Mike Trout 25th overall, most teams don’t hit on every first round pick they have.

There are several ways to acquire both professional and amateur talent to construct a World Series championship team. There’s free agency, trades, waiver pickups, the Rule 5 Draft, international signings, and of course the first-year player draft that takes place every June. The first-year player draft is MLB’s version of the NFL, NBA, or NHL Drafts, where high school and college players make the leap to the professional level. In baseball, the MLB Draft is one of the most important tools teams use to build their teams, whether it’s drafting homegrown players that are part of an organization for years to come or drafting guys that develop into top prospects that can be used as trade bait to acquire stars from other teams. A team’s success or failure in a particular draft can either greatly enhance or greatly debilitate an MLB club’s ability to contend for a World Series.

That is why I decided to evaluate how every MLB team has fared with their top 100 picks in each June draft from 1987 to 2010. To evaluate every player chosen, I used Wins Above Replacement (WAR). WAR is considered by many to be the single best statistic to calculate a baseball player’s performance in all aspects of a game including hitting, pitching, fielding, and baserunning. The higher a player’s WAR is, the better the player performed and contributed to his team’s success. WAR is not standardized and there are several ways to calculate it, which is why I combined both Fangraphs and Baseball Reference by averaging them together to determine a player’s final WAR.

I chose to start with 1987 because that was the first year that there was one sole draft that teams could pick amateur players from. In prior years there were other drafts such as the January Amateur Draft (1966–1985), the January Secondary Draft (1966–1985), the June Secondary Draft (1966–1986), and the August Legion Draft (1965–1966). I chose to conclude with 2010 because of how many active players there are currently that were drafted after 2010, and since WAR is a cumulative stat, most players still haven’t reached their maximum WAR.

Instead of simply calculating the total WAR of every player each team drafted, I wanted to consider where the team was picking. It’s obviously easier to find the best players when you’re picking at the top of a draft than it is picking at the bottom. So I assigned an “Expected WAR” to each draft slot 1–100, and subtracted the “Expected WAR” of the draft slot in which a player was chosen from the player’s “Actual WAR” (Actual WAR — Expected WAR) to determine if the player exceeded or fell below expectations for that particular slot.

To calculate the Expected WAR for each draft slot, I averaged the WAR of every player drafted in each slot 1–100 from 1987 to 2010, ensuring a large enough sample size. I couldn’t simply use these average WAR numbers as the expected WAR because they were skewed. For instance, the average WAR for the 5th pick was higher than the average WAR for the 4th pick. You would clearly expect the average WAR for the 4th pick to be higher than the 5th pick. I used a logarithmic line-of-best-fit which fit the data best. The logarithmic model had an R-squared value of 0.6633 which means that the model explains 66.33% of the variability in our y-variable “Average WAR.” I then used the equation from the model and plugged in each draft slot as the x-variable to calculate the “Expected WAR.”

The graph below shows the Average WAR for each draft slot, with the line representing the Expected WAR for each draft slot.