Baseball Notes

Two posts ago, when I wrote a piece entitled “When looking for a good hitter,” a debate was sparked amongst some peers outside of cyberspace and in the real world as to the validity of Value Over Replacement Player (VORP) and how it is used to compare players.

When looking at VORP and its meaning, you are really following a trail of bread crumbs built on other stats (some obscure, some not so much) that eventually leads you to a certain player’s value over a cheap/AAA/waiver-wire replacement. Let’s explore.

According to Baseball Prospectus, VORP is defined as:

Value Over Replacement Player. The number of runs contributed beyond what a replacement-level player at the same position would contribute if given the same percentage of team plate appearances. VORP scores do not consider the quality of a player’s defense.

That is all well and good, but there are a number of questions that spring from this. How do you find the number of runs contributed? “At the same position” means you are comparing like players, but how? How do you define a “replacement-level” player?

Let’s start at the beginning. According to Wikipedia, VORP was developed by Keith Woolner to determine a player’s offensive contributions beyond this fictitious replacement lever player, also known as “freely available talent.” Usually this person is considered to be the last player on your bench, the average guy you can call up from Triple-A or someone who is readily available on the waiver wire.

Runs Contributed: This portion of the formula looks at how many runs did this player produce in a given time period or season. There are a lot of ways to measure this; Bill James’ Runs Created or Extrapolated Runs. But, the run measurement used by Woolner in VORP is Equivalent Runs, or EqR, or the amount of runs produced at the plate while playing at a particular position. The formula is:

EqR = 5 * OUT * EqA^2.5 (where OUT equals the total number of outs made by a player and EqA is Equivalent Average)

So now we have another uncommon statistic, Equivalent Average (EqA). EqA is designed to show productivity per out or to measure total offensive value per out. Since baseball is a game that is not controlled by a clock, they only way to measure a game is by outs, so essentially, you want to know how effective someone is per out (for more on EqA, click here, this article also shows some convincing correlations and RMSE scores when comparing EqA to other stats). In it’s design, it is supposed to look and read just like batting average. So the most average player in MLB will always have a .260 EqA. Anything lower than this is considered below-average while .300 would be really good and .320 would be all-star level, etc. The formula for Raw EqA is:

(H + TB + 1.5*(BB + HBP + SB) + SH + SF) divided by (AB + BB + HBP + SH + SF + CS + SB)

FINALLY, some statistics we can all understand. Raw EqA is then normalized into EqA accounting for league difficulty, home ballpark, etc., using a process you don’t really want me to get into. Think of normalizing like this: Creating 50 runs in 1917 was much harder to do than in 2007, so a process was found to stabilize all of the numbers. Baseball Reference utilizes this as well on all of their player pages (and you can also see normalized data for extreme low-scoring scenarios and extreme high-scoring scenarios).

So by using every offensive stat possible, you can deduct the runs created or contributed by a player to determine the “Value” part of VORP.

At the Same Position: After checking this a couple of times, VORP was truthfully designed to be used as a tool to compare like positions, such as comparing catchers to catchers or first basemen to first basemen. Well…..sort of. That’s where we get the next part of the equation.

Replacement Level Player: This is where is starts to get a little murky. A big critique of VORP is it’s seemingly random assignment of what is replacement level when discussing offense. There are two schools of thought I can find that seem the most accurate, though.

One describes replacement level as 70 points below the positional OPS average. Essentially, you find the average OPS for each position, and 70 points below that number is your respective replacement level. For example, the average OPS for an NL second basemen in 2005 was about .750. Any second basemen with an OPS of .680 or lower would be considered replacement level.

The second describes replacement level as 80% of league average of runs per out. There are two exceptions, however. Catchers, who are valuable in many other areas, are measured at 75% of league average, while first basemen and DHs are measured at 85% of league average because of their lack of defensive contributions.

Still, both theories are arbitrary and educated guesses at best. But it would be safe to assume that the numbers are not too far off, especially if you were considering what to do with players on your team who were 70 points below their positional league average in OPS.

So, when all is said and done you basically have three components:

1. Runs contributed or created above,
2. a replacement level player or a mythical player with production less than league average,
3. at their respective position.

Your basic and common sabermetric stats often become building blocks on each other, as you would see if you were to examine others in depth. But most of these revolve around a central concept; the concept of creating runs and doing so in the most productive way possible - which is to say by using as few outs as possible.

I would be happy to dissect any other stats you feel might need explaining.

Much of the information from this post came from www.baseballprospectus.com, www.stathead.com, and www.wikipedia.com.