Aneez Kanji evalutates the IMPACT that a Major League Baseball batter has while at the plate.

Read the original 'Methodology' post to see how the IMPACT STAT is calculated

Saturday, March 8, 2008

The Impact Stat - Methodology

As a baseball fan, and close follower of the game I have always been puzzled by the statistics highlighting an individual batter's offensive production. Baseball is a team game, where each batter's ultimate success of circling the bases and crossing home-plate is intrinsically linked to the batters before or after them in the lineup.

The goal of every batter should be to keep the lineup moving. This has been cited as one of the reasons of the Boston Red Sox success in 2007.

Here are the four most popular calculations along with my critique of each, followed by my idea for a new method of calculating production:

Batting Average (BA): Total Hits/Total at-bats
The BA is the oldest, most 'pure', and most simple of the calculations. It weighs all hits equally. A single is just as valuable as double or a homerun. The BA however excludes Walks which can be just as producitve as a single, and in the right situation (which is explained futher on this page) a walk is even more valuable than a single.

On Base Percentage (OBP):
(Total Hits + Walks + Hit by pitch) / (At bats + Walks + hit by pitch + sacrifice flies)
The OBP is a better calcuation than the BA as it takes into account walks, and hit by a pitch. However Sacrifice Flies is added into denominator which penalizes a batter. I feel that a sacrifice fly is just as strategic as a sacrifice bunt and should be excluded from this calculation.

Slugging (S): (singles + (2x doubles) + (3x triples) + (4x homeruns) / At bats
Slugging factors for the number of bases achived during each at bat. The more bases achieved per at bat, the better. The closer the runner is home plate, the better the chances of scoring a run. I agree that when comparing to singles to homeruns, there is no contest - homeruns are much more valuable than singles. However it can be argued that depending on the situation, there is no real difference between a double and a triple. I'll explain my view further on this page.

OBP+S: This is simply straight addition of the above two statistics. This statistic does not really tell me much more new information of a batters plate performance, it just seems to serve as 'eye-candy' for fans looking for a number close to 1.000

As I mentioned earlier, these stats are mainly individual, and have limitations.

I've looked over other statistics which take into account other factors such as runners on base, runners in scoring position, facing lefties or righties, taking into account the feild, pitch count and others. These stats breakdown the situations too much, and an overall picture of performance cannot be taken.

The Impact Stat takes into account everything a batter does at home plate to move along the batting line up, even if it includes an out. As a fan watching the game each of the following events keeps the inning alive and leads to the chance of a run being scored.

The Impact Stat is calucated by adding the below factors divided by Total Plate Appearances:

Hits: Whether a single/double/triple/homerun each hit weighed the same, similar to calcualting batting average. As an observer of the game, I tend to find very little overall difference when a batter hits a double or a triple. If someone was on base ahead of them, generally that runner will score. If the next batter gets a hit, even a single, generally runner on 2nd or 3rd (scoring position) will score.

Walks: Walks are weighed the same as a hit. The batter has done their job by keeping the lineup moving and in most cases a walk will increase the pitch count, and reduce the number of batters a pithcer faces. During the later innings of a game when the starting pitcher is nearing the maximum pitch count of normally 100 pitches forcing a walk could end the pitchers game early.

Sacrifice Flies/Hits: This is viewed in a negative manner in the OBP calculation. A Sacrifice Fly /Hit / Bunt generally results in runner moving to a better scoring position, or scoring a run.

Hit By a Pitch: Getting hit by a 90+ mph pitch does a bit more than tickle. Like a walk it gets a runner on base, and moves along the lineup.

Intentional Walks: Intentional walks are already counted by MLB under 'walks', however I thought it would be important to essentianly give 'extra credit' for an intentional walk as the batter moves along the line up twice as fast than any other at bat. Basically you get two batters for the price of one. USA today had an insightful article about intentional walks to Barry Bonds a few years ago.

Here is how the Impact Stat compared to the Batting Average | OBP | SLG | OBP+S in 2007 for the American League (click to enlarge):

- Battters displayed have at least 502 total plate appearances
- Pitches Faced At Bat (PFAB) for my own personal interest. I rate 4.0 or higher as excellent as you are actually wearing the pitchers down and facing good pitches
-The leader in each category is highlighted in dark green, and the next best 9 or 10 in light green.

Highlights of The IMPACT STAT:
5th - J Posada ranks within the Top 10 of each of the categories, showing him as a consistent threat at the plate

4th - A Rodriguez, the AL's MVP was first in SLG, and was ahead of Ortiz by just .001 in OPS, however his batting average is not within the top 10 and his overall Impact is behind Ortiz by .017 points.

3rd - Batting Title holder M Ordonez had a league leading batting average of .363 and falls 3rd in the Impact Category

2nd - V Guerrero falls within the top 10 in each category, and although he doesn't lead any specific one, he places 2nd for Impact.

1st - D Ortiz, contender for AL MVP, and batting title shows that he posed the biggest threat of any player at the plate causing an IMPACT .468 of the time!

Other Noteables:
- C Granderson fell within the Top 10 of Slugging and OPS (lots of triples), however his overall Impact ranked 40th.

- M Ramirez didn't place in the Top 10 for any of the traditional batting statistics, however he places in spot 8 for IMPACT, showing he is a bigger threat at the plate that what his batting average and other stats show.

- Boston have an incredible 7 players in the Top 40, NYY and DET have 5 each, LAA and CLE have 4 each.

I will expanding my research in the coming days and weeks so stay tuned!

Please send any feedback to

Thanks - Aneez Kanji


Danner said...

Hmmm.... looks interesting.

Karim Kanji said...

wow. amazing. look forward to your appearance on Hardcore Sports

The Kanji's said...

I don't know if Sacrifice Flies/Hits should be weighted as equally as the other areas. Is there any measure to see what percentage of sac flies/hits result in the advancement of a runner by a base? If it's less than 50%, maybe this stat should be weighted lower than the others?

Aneez Kanji said...

If there is no advancement of a runner it's just called an out. By it's title, a 'Sacrifice' means the batter got out at the expense of moving the runner along.

Karim Kanji said...

All sacrifice flies and sacrifice hits result in runners moving along. Either the batter is safe or someone else is safe. (Note that a base has been advanced in both cases.)

JD said...

You know you're basically measuring OBP, right?

Aneez Kanji said...

OBP doesn't take into account sac flies or sac bunts as positive production. OBP also doesn't take into account the double positive of an IBB (ie two batters for the price of one).

Christopher said...

This stat is ridiculous. There's no justification for weighting IBB double a walk. They're identical. Otherwise it is OBP without SF in the denominator... whoopie.

Aneez Kanji said...

Thanks for the comments Christopher.

The IMPACT STAT measures EVERYTHING a batter does at a plate which is productive for the team, not just himself. It's like looking at Goals AND Assists by a hockey player, or a hockey player's +/- stat.

The reason I count IBB as double is because it basically guarantees an increase in run potential. Check the Barry Bonds article in the 'Methodology' post.

Which situation would you rather have, a batter at the plate with no one on, or a batter at the plate with a runner on first?

I am aware that the IMPACT STAT is similar to OBP in the same manner that OBP is similar to BA.